Endoluminal prosthesis deployment devices and methods

ABSTRACT

Catheter systems and methods for deployment of an endoluminal prosthesis in a body lumen of a patient while maintaining control of a position of the endoluminal prosthesis during the deployment process. Some of the systems and methods are configured to minimize frictional forces of components of the catheter systems during deployment procedures.

RELATED APPLICATIONS

This application is a continuation application of U.S. patentapplication Ser. No. 15/737,881, filed Dec. 19, 2017, which is anational stage application under 35 U.S.C. § 371 of International PatentApplication No. PCT/US2016/044583, filed Jul. 28, 2016, which claimspriority from U.S. Provisional Patent Application Ser. No. 62/199,168,filed Jul. 30, 2015, and U.S. Provisional Patent Application Ser. No.62/201,046, filed Aug. 4, 2015, all of which are incorporated byreference herein in their entirety.

BACKGROUND

An aneurysm is a vascular defect indicated generally by an expansion andweakening of the wall of an artery of a patient. Aneurysms can developat various sites within a patient's body. Thoracic aortic aneurysms(TAAs) or abdominal aortic aneurysms (AAAs) are manifested by anexpansion and weakening of the aorta which is a serious and lifethreatening condition for which intervention is generally indicated.Existing methods of treating aneurysms include invasive surgicalprocedures with graft replacement of the affected vessel or body lumenor reinforcement of the vessel with a graft.

Surgical procedures to treat aortic aneurysms can have relatively highmorbidity and mortality rates due to the risk factors inherent tosurgical repair of this disease as well as long hospital stays andpainful recoveries. This is especially true for surgical repair of TAAs,which is generally regarded as involving higher risk and more difficultywhen compared to surgical repair of AAAs. An example of a surgicalprocedure involving repair of an AAA is described in a book titledSurgical Treatment of Aortic Aneurysms by Denton A. Cooley, M. D.,published in 1986 by W. B. Saunders Company.

Due to the inherent risks and complexities of surgical repair of aorticaneurysms, minimally invasive endovascular repair has become awidely-used alternative therapy, most notably in treating AAAs. Earlywork in this field is exemplified by Lawrence, Jr. et al. in“Percutaneous Endovascular Graft: Experimental Evaluation”, Radiology(May 1987) and by Mirich et al. in “Percutaneously Placed EndovascularGrafts for Aortic Aneurysms: Feasibility Study,” Radiology (March 1989).

When deploying endoluminal prosthesis type devices by catheter or othersuitable instrument, it may be advantageous to have a flexible and lowprofile endoluminal prosthesis such as a stent graft and catheter systemfor passage through the various guiding catheters as well as thepatient's sometimes tortuous anatomy. Many of the existing endovascularprostheses and methods for treatment of aneurysms as well as otherindications within body lumens of patients, while representingsignificant advancement over previous devices and methods, use systemshaving relatively large transverse profiles, often up to 24 French.Also, such existing systems may have greater than desired lateralstiffness, which can complicate the delivery process, particularly foruse in treatment of vascular defect sites that include a high degree ofcurvature or angulation. Even with more flexible low profile deliverysystems, deployment of endovascular prostheses in highly angulated andcurved vessels may be problematic due to difficulties with visualizationor imaging of the orientation of the prostheses during the deploymentprocess. In addition, such angulated or tortuous anatomies may alsoinduce undesirable amounts of friction between components of cathetersystems that may make operation of the catheter system challenging insome situations. As such, minimally invasive endovascular treatment ofaneurysms as well as other indications within a body lumen of a patientmay not be available for many patients that would benefit from such aprocedure and can be more difficult to carry out for those patients forwhom the procedure is indicated.

What have been needed are catheter systems and methods of using thesecatheter systems that are adaptable to a wide range of patient anatomiessuch that suitable endoluminal prostheses may be safely and reliablydeployed using a flexible low profile catheter system.

SUMMARY

Some embodiments of a catheter system for deploying an endoluminalprosthesis in a body lumen of a patient include a flexible elongatechassis having a proximal end, a distal end, a distal section and anoverall column strength sufficient for advancement of the chassisthrough a body lumen of a patient. The catheter system may also includea self-expanding tubular endoluminal prosthesis disposed in aconstrained state over the distal section of the chassis. In addition,such a catheter system may include a thin, flexible, resilient extensionincluding a proximal end which is secured in fixed relation to theelongate catheter chassis and a distal end which is disposed radiallyoutward from an outside surface of the chassis and distal of theproximal end of the extension. For such a catheter system, the extensionmay extend through a wall of a distal end of the endoluminal prosthesiswith the extension in a radially constrained state such that theextension at least partially captures a distal segment of theendoluminal prosthesis and restricts proximal displacement of theendoluminal prosthesis relative to the chassis. In some cases, such acatheter system may include a plurality of such extensions.

Some embodiments of a catheter system for deploying an endoluminalprosthesis in a body lumen of a patient include a flexible elongatechassis having a proximal end, a distal end, a distal section and anoverall column strength sufficient for advancement of the chassisthrough a body lumen of a patient. The catheter system may also includea self-expanding tubular endoluminal prosthesis disposed in aconstrained state over the distal section of the chassis. In addition,the catheter system may also include a rigid extension having a proximalend which is secured in fixed relation to the elongate catheter chassis,and a distal end which is disposed radially outward from an outsidesurface of the chassis and distal of the proximal end of the extension.For such a catheter system, the extension may extend through a wall of adistal end of the endoluminal prosthesis with the extension in aradially constrained state such that the extension at least partiallycaptures a distal segment of the endoluminal prosthesis and restrictsproximal displacement of the endoluminal prosthesis relative to thechassis. In some cases, such a catheter system may include a pluralityof such rigid extensions.

Some embodiments of a method for deploying an endoluminal prosthesis ina body lumen of a patient include advancing a catheter system fordeployment of an endoluminal prosthesis into the body lumen of thepatient until the endoluminal prosthesis of the catheter system isdisposed at a treatment site. An outer constraint may then be removedfrom the endoluminal prosthesis while an extension prevents proximalaxial movement of the endoluminal prosthesis relative to the chassis.Such an extension may include a proximal end which is secured in fixedrelation to an elongate catheter chassis and a distal end which isdisposed radially outward from an outside surface of the chassis anddistal of the proximal end of the extension. The extension also extendsthrough a wall of a distal end of the endoluminal prosthesis with theextension in a radially constrained state such that the extension atleast partially captures a distal segment of the endoluminal prosthesis.The endoluminal prosthesis is then allowed to self-expand such that anoutside surface of the endoluminal prosthesis contacts an inside surfaceof the patient's body lumen. The chassis and extension may then beproximally retracted such that the extension passes axially through thewall of the distal end of the endoluminal prosthesis and fullydisengages the endoluminal prosthesis.

Some embodiments of a catheter system for deploying an endoluminalprosthesis in a body lumen of a patient include a flexible elongatechassis having a proximal end, a distal end, a distal section and anoverall column strength sufficient for advancement of the chassisthrough a body lumen of a patient. Such a catheter system may alsoinclude a self-expanding tubular endoluminal prosthesis disposed in aconstrained state over the distal section of the chassis. In addition,such a catheter system may include a thin, flexible, axial belt having afixed end which is secured in fixed relation to the elongate catheterchassis and a free end which is disposed opposite the fixed end. Forsuch catheter system embodiments, the axial belt may form a loop thatextends proximally from the fixed end and free end through a distalsegment of a wall of the endoluminal prosthesis. The free end of theaxial belt is releasably secured in fixed relation to the chassis with acircumferential belt which is disposed about the chassis and free endsuch that the loop captures a distal segment of the endoluminalprosthesis and restricts proximal displacement of the endoluminalprosthesis relative to the chassis.

Some embodiments of a method for deploying an endoluminal prosthesis ina body lumen of a patient include advancing a catheter system fordeployment of an endoluminal prosthesis into the body lumen of thepatient until the endoluminal prosthesis of the catheter system isdisposed at a treatment site. An outer constraint may be removed fromthe endoluminal prosthesis while an axial belt restricts proximal axialmovement of the endoluminal prosthesis relative to the chassis. Such anaxial belt may include a fixed end which is secured in fixed relation tothe elongate catheter chassis and a free end which is disposed oppositethe fixed end. The axial belt forms a loop that extends proximally fromthe fixed end and free end through a distal segment of a wall of theendoluminal prosthesis with the free end of the axial belt releasablysecured in fixed relation to the chassis with a circumferential beltwhich is disposed about the chassis and free end such that the loopcaptures a distal segment of the endoluminal prosthesis. The endoluminalprosthesis may be allowed to self-expand by removal of the constraintsuch that an outside surface of the endoluminal prosthesis contacts aninside surface of the patient's body lumen. The circumferential belt isthen released from the axial belt and axial belt from the distal segmentof the endoluminal prosthesis so as to allow the endoluminal prosthesisto be fully deployed and engage the body lumen. The chassis and axialbelt may then be proximally retracted such that the axial belt iswithdrawn from the wall of the distal end of the endoluminal prosthesis.

Some embodiments of a catheter system for deploying an endoluminalprosthesis in a body lumen of a patient include a flexible elongatechassis having a proximal end, a distal end, a distal section and anoverall column strength sufficient for advancement of the chassisthrough a body lumen of a patient. Such a catheter system may alsoinclude a self-expanding tubular endoluminal prosthesis disposed in aconstrained state over the distal section of the chassis. In addition,such a catheter system may include a plurality of axial release wires,with each axial release wire having a proximal end, a distal end and adistal section. For such an embodiment, the distal section of eachrelease wire may extend through a distal segment of a wall of theendoluminal prosthesis with the distal section releasably secured infixed relation to a pair of axially spaced bushings which are secured toand extend radially outward from the chassis. Such a structure may beconfigured so as to form a loop structure or otherwise enclosedstructure between the distal section, the axially spaced bushings and anoutside surface of the chassis, such that this loop structure releasablycaptures a distal segment of the endoluminal prosthesis and restrictsproximal displacement of the endoluminal prosthesis relative to thechassis.

Some embodiments of a catheter system for deploying an endoluminalprosthesis in a body lumen of a patient include a flexible elongatechassis having a proximal end, a distal end, and a column strengthconfigured for advancement of the chassis through a body lumen of apatient. Such a catheter system may also include a self-expandingtubular endoluminal prosthesis disposed in a constrained state at thedistal end of the chassis. In addition, such a catheter system mayinclude a tubular everting sheath which has an inner section whichincludes a first diameter, a fixed end which is secured in fixedrelation to the chassis and an endoluminal prosthesis section that isdisposed over and radially constrains the endoluminal prosthesis in theconstrained state. The tubular everting sheath may also have an outersection that is everted back over the endoluminal prosthesis section ofthe inner portion. The outer section may include a retraction end and asecond diameter which is larger than the first diameter of the innersection such that the outer section is readily slideable over the innersection during retraction of the retraction end and eversion of theeverting sheath.

Some embodiments of a catheter system for deploying an endoluminalprosthesis in a body lumen of a patient may include a flexible elongatechassis having a proximal end, a distal end, and a column strengthconfigured for advancement of the chassis through a body lumen of apatient. Such a catheter system may also include a self-expandingtubular endoluminal prosthesis disposed in a constrained state at thedistal end of the chassis. In addition, such a catheter system mayinclude a tubular everting sheath which has an inner section whichincludes a fixed end which is secured in fixed relation to the chassisand an endoluminal prosthesis section that is disposed over and radiallyconstrains the endoluminal prosthesis in the constrained state. Thetubular everting sheath may also have an outer section that is evertedback over the endoluminal prosthesis section of the inner portion. Theouter section may also include a retraction end. The everting sheath mayalso include a PTFE material having a closed cell microstructure with nodistinct fibrils interconnecting adjacent nodes such that the outersection is readily slideable over the inner section.

Some embodiments of a method for deploying an endoluminal prosthesis ina body lumen of a patient include advancing a catheter system fordeployment of an endoluminal prosthesis into the body lumen of thepatient until the endoluminal prosthesis of the catheter system isdisposed at a treatment site in a constrained state. The endoluminalprosthesis is held in the constrained state by an endoluminal prosthesissection of an inner section of a tubular everting sheath. In some cases,the inner section may have a first diameter and a fixed end which issecured in fixed relation to an elongate chassis of the catheter system.An outer constraint may be removed from the endoluminal prosthesis byproximally retracting a retraction end of an outer section of thetubular everting sheath. Such an outer section may be everted back overthe endoluminal prosthesis section of the inner section and include asecond diameter which is larger than the first diameter of the innersection. The endoluminal prosthesis may be thus allowed to self-expandas the endoluminal prosthesis section of the inner section is proximallyeverted so as to remove radial constraint from the endoluminalprosthesis. As the endoluminal prosthesis self-expands, an outsidesurface of the endoluminal prosthesis may then engage an inside surfaceof the patient's body lumen.

Some embodiments of a method for deploying an endoluminal prosthesis ina body lumen of a patient include advancing a catheter system fordeployment of an endoluminal prosthesis into the body lumen of thepatient until the endoluminal prosthesis of the catheter system isdisposed at a treatment site in a constrained state. For such a cathetersystem, the endoluminal prosthesis may be held in the constrained stateby an endoluminal prosthesis section of an inner section of a tubulareverting sheath. Such a tubular everting sheath may include a PTFEmaterial having a closed cell microstructure with no distinct fibrilsinterconnecting adjacent nodes. The inner section may include a fixedend which is secured in fixed relation to an elongate chassis of thecatheter system. An outer constraint may then be removed from theendoluminal prosthesis by proximally retracting a retraction end of anouter section of the tubular everting sheath. Such an outer section maybe everted back over the endoluminal prosthesis section of the innersection. The endoluminal prosthesis may then be allowed to self-expandas the endoluminal prosthesis section of the inner section is proximallyeverted so as to remove radial constraint from the endoluminalprosthesis. As the endoluminal prosthesis self-expands, an outsidesurface of the endoluminal prosthesis may engage an inside surface ofthe patient's body lumen.

Some embodiments of a catheter system for deploying an endoluminalprosthesis in a body lumen of a patient may include a flexible elongatechassis having a proximal end, a distal end, a distal section and anoverall column strength sufficient for advancement of the chassisthrough a body lumen of a patient. The catheter system may also includea self-expanding tubular endoluminal prosthesis disposed in aconstrained state over the distal section of the chassis and a thin,flexible, resilient extension that extends through a wall of a distalend of the endoluminal prosthesis. The extension may be disposed in aradially constrained state such that the extension at least partiallycaptures a distal segment of the endoluminal prosthesis and restrictsproximal displacement of the endoluminal prosthesis relative to thechassis. The extension may include a proximal end which is secured infixed relation to the elongate catheter chassis and a distal end whichis disposed radially outward from an outside surface of the chassis anddistal of the proximal end of the extension. In addition, the cathetersystem may further include a tubular everting sheath which has an innersection which includes a fixed end which is secured in fixed relation tothe chassis and an endoluminal prosthesis section that is disposed overand radially constrains the endoluminal prosthesis and extension in theconstrained state. The tubular everting outer sheath may also have anouter section that is everted back over the endoluminal prosthesissection of the inner portion, the outer section including a retractionend which is disposed at an opposite end of the everting sheath relativeto the fixed end.

Some embodiments of a method for deploying an endoluminal prosthesis ina body lumen of a patient may include advancing a catheter system fordeployment of an endoluminal prosthesis into the body lumen of thepatient until the endoluminal prosthesis of the catheter system isdisposed at a treatment site. For such a catheter system, theendoluminal prosthesis and a resilient, flexible, extension that atleast partially captures a distal segment of the endoluminal prosthesismay both be held in a constrained state by an endoluminal prosthesissection of an inner section of a tubular everting sheath. An outerconstraint may thereafter be removed from the endoluminal prosthesis andthe extension by proximally retracting a retraction end of an outersection of the tubular everting sheath. Retraction of the outer sectionmay be carried out by the outer section being everted back over theendoluminal prosthesis section of the inner section during the proximalretraction while the extension prevents proximal axial movement of theendoluminal prosthesis relative to a flexible, elongate chassis of thecatheter system. The endoluminal prosthesis and extension may then beallowed to self-expand such that an outside surface of the endoluminalprosthesis engages an inside surface of the patient's body lumen.Finally, the chassis and extension may be proximally retracted such thatthe extension passes axially through the wall of the distal end of theendoluminal prosthesis and no longer engages the distal segment of theendoluminal prosthesis.

Some embodiments of a method of loading an endoluminal prosthesis into asheath which is configured to constrain the endoluminal prosthesisinclude passing a plurality of thin high tensile tethers loops throughan end of the endoluminal prosthesis. The plurality of tether loops isalso passed through an inner lumen of the sheath. An end of the sheathis restrained and both ends of each of the tether loops are pulled onsimultaneously in a direction away from the endoluminal prosthesis suchthat the tether loops are pulled through the inner lumen of the sheathand axial tension is thereby applied to the end of the endoluminalprosthesis such that the endoluminal prosthesis is radially compressedand constrained as it is pulled into a funnel section of the inner lumenof the sheath to an endoluminal prosthesis section within the innerlumen of the sheath. Thereafter, only one side of each of the tetherloops is pulled on and an opposite end of each tether loop is releaseduntil each of the tether loops is pulled out of the endoluminalprosthesis and the inner lumen of the sheath.

Certain embodiments are described further in the following description,examples, claims and drawings. These features of embodiments will becomemore apparent from the following detailed description when taken inconjunction with the accompanying exemplary drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an elevation view of a catheter system for deploying anendoluminal prosthesis in a body lumen of a patient disposed in a bodylumen.

FIG. 2 is an enlarged view in partial section of the catheter system andbody lumen indicated by the encircled portion 2-2 of FIG. 1.

FIG. 3 is an elevation view in partial section of the endoluminalprosthesis of FIG. 2 in a partially deployed state.

FIG. 4 is an elevation view in partial section of the endoluminalprosthesis of FIG. 2 in a fully deployed state.

FIG. 5 is an elevation view in partial section of the endoluminalprosthesis of FIG. 2 in a fully deployed state with an elongate chassisand extensions of the catheter system withdrawn from the patient's bodylumen.

FIG. 6 is an elevation view of the elongate chassis and extensions of acatheter system embodiment.

FIG. 7 is a transverse cross section of the elongate chassis of FIG. 6indicated by lines 7-7 of FIG. 6.

FIG. 8 is an enlarged elevation view of an extension embodiment.

FIG. 9 is an elevation view of an endoluminal prosthesis embodiment asshown in FIGS. 2-5.

FIG. 10 is a transverse cross section of the endoluminal prosthesisembodiment of FIG. 9 taken along lines 10-10 of FIG. 9.

FIG. 11 is an elevation view of a section of an elongate chassis andextensions extending therefrom wherein the extensions have been cut froma tubular structure of the elongate chassis.

FIG. 12 is a transverse cross section of the elongate chassis andextensions of FIG. 11 taken along lines 12-12 of FIG. 11.

FIG. 13 is an elevation view of the elongate chassis, extensions andnosecone of a catheter system embodiment.

FIG. 14 is a transverse cross section of the elongate chassis andextensions of FIG. 13 taken along lines 14-14 of FIG. 13.

FIG. 15 is an elevation view of partial section of a distal portion of acatheter system embodiment.

FIG. 16 is a transverse cross section of the outer sheath, nosecone andextensions of the catheter system of FIG. 15 taken along lines 16-16 ofFIG. 15.

FIG. 17 is an elevation view of an elongate chassis, extensions andnosecone of a catheter system embodiment.

FIG. 18 is a transverse cross section of the elongate chassis of thecatheter system of FIG. 17 taken along lines 18-18 of FIG. 17.

FIG. 19 is an elevation view of a catheter system for deploying anendoluminal prosthesis in a body lumen of a patient.

FIG. 20 is an enlarged view in partial section of the catheter systemindicated by the encircled portion 20-20 of FIG. 19.

FIG. 21 is an enlarged view in partial section of the catheter systemindicated by the encircled portion 21-21 of FIG. 20.

FIG. 22 is a transverse cross section of the catheter system of FIG. 21taken along lines 22-22 of FIG. 21.

FIG. 23 is an elevation view in partial section of the catheter systemof FIG. 19 disposed within a patient's body lumen.

FIG. 24 is an elevation view in partial section of the catheter systemof FIG. 19 disposed within a patient's body lumen with an outer sheathproximally retracted and the endoluminal prosthesis of the cathetersystem partially deployed within the patient's body lumen.

FIG. 25 is an elevation view in partial section of the catheter systemof FIG. 19 disposed within a patient's body lumen with the endoluminalprosthesis fully deployed and engaging the patient's body lumen.

FIG. 26 is an elevation view in partial section of a distal portion of acatheter system embodiment for delivery of an endoluminal prosthesis ina body lumen of a patient.

FIG. 27 is an elevation view in partial section of a distal portion of acatheter system embodiment for delivery of an endoluminal prosthesis ina body lumen of a patient.

FIG. 28 is an enlarged view of the distal portion of the catheter systemof FIG. 27.

FIG. 29 is a transverse cross section of the elongate chassis of thecatheter system of FIG. 28 taken along lines 29-29 of FIG. 28.

FIG. 30 is an elevation view of the catheter system of FIG. 27 disposedwithin a body lumen of a patient and the endoluminal prosthesis of thecatheter system deployed and engaged with an inner surface of the bodylumen.

FIG. 31 is an elevation view of a catheter system for deploying anendoluminal prosthesis in a body lumen of a patient.

FIG. 32 is an enlarged view in partial section of the catheter systemand body lumen indicated by the encircled portion 32-32 of FIG. 31.

FIG. 33 is an enlarged view in partial section of the catheter systemand body lumen indicated by the encircled portion 33-33 of FIG. 31.

FIG. 34 is a transverse cross section of the catheter system of FIG. 33taken along lines 34-34 of FIG. 33.

FIG. 35 is an enlarged elevation view in section of a wall portion ofthe catheter system indicated by the encircled portion 35-35 shown inFIG. 32.

FIG. 36 is a transverse cross section of the catheter system of FIG. 32taken along lines 36-36 of FIG. 32.

FIG. 37 is an elevation view of an everting sheath embodiment of acatheter system embodiment.

FIG. 38 is an enlarged view of a transition section between an innersection and an outer section of the everting sheath of FIG. 37 asindicated by the encircled portion 38-38 of FIG. 37.

FIG. 39 is an enlarged view of a wall portion of the outer section ofthe everting sheath of FIG. 38 as indicated by the encircled portion39-39 of FIG. 38.

FIG. 40 is an enlarged view of a funnel section disposed at a retractionend of the outer section of the everting sheath of FIG. 37 as indicatedby the encircled portion 40-40 of FIG. 37.

FIG. 41 is an end view of the outer section of the everting sheath ofFIG. 37.

FIG. 42 is an elevation view in partial section showing a distal portionof the catheter system of FIG. 31 disposed within a body lumen of apatient.

FIG. 43 is an elevation view in partial section showing a distal portionof the catheter system of FIG. 31 disposed within a body lumen of apatient with an everting sheath partially retracted and an endoluminalprosthesis of the catheter system partially deployed.

FIG. 44 is an elevation view in partial section showing a distal portionof the catheter system of FIG. 31 disposed within a body lumen of apatient with an everting sheath partially retracted and an endoluminalprosthesis of the catheter system partially deployed.

FIG. 45 is an elevation view in section showing the endoluminalprosthesis of the catheter system of FIG. 31 fully deployed and engagingan inside surface of the patient's body lumen.

FIG. 46 shows a distal portion of the catheter system of FIG. 31disposed in an iliac body lumen of a patient.

FIG. 47 is an enlarged view in partial section of another embodiment ofthe catheter system and body lumen indicated by the encircled portion32-32 of FIG. 31 that includes flexible resilient extensions operativelysecured to the chassis and passing through a distal segment of anendoluminal prosthesis embodiment.

FIG. 48 is an elevation view in partial section showing a distal portionof the catheter system of FIG. 31 disposed within a body lumen of apatient, the catheter system including the optional extensionsoperatively secured to the chassis as shown in FIG. 47.

FIG. 49 is an elevation view in partial section showing a distal portionof the catheter system of FIG. 48 disposed within a body lumen of apatient with an everting sheath partially retracted and an endoluminalprosthesis of the catheter system partially deployed.

FIG. 50 is an elevation view in partial section showing a distal portionof the catheter system of FIG. 48 disposed within a body lumen of apatient with an everting sheath.

FIG. 51 is an elevation view in partial section showing a distal portionof the catheter system of FIG. 48 disposed within a body lumen of apatient with an everting sheath completely retracted and the optionalextensions retracted from the endoluminal prosthesis.

FIG. 52 is an elevation view in section showing the endoluminalprosthesis of the catheter system of FIG. 48 fully deployed and engagingan inside surface of the patient's body lumen.

FIG. 53 is an elevation view of an endoluminal prosthesis embodiment andoptional elongate catheter chassis being loaded into an everting sheathembodiment.

FIG. 54 is an elevation view of the everting sheath embodiment of FIG.53 with the endoluminal prosthesis and elongate catheter chassis beingdrawn into the funnel section of the everting sheath such that theendoluminal prosthesis and resilient extensions of the optional chassisare radially constrained.

FIG. 55 is an elevation view of the everting sheath of FIG. 53 with theendoluminal prosthesis completely loaded into an endoluminal prosthesissection of the everting sheath.

FIG. 56 shows a thin high tensile tether being pulled through theeverting sheath and out of an end of the fully loaded endoluminalprosthesis of FIG. 55.

FIG. 57 shows a more detailed view in partial section of the thin hightensile tether being pulled out of an end of the fully loadedendoluminal prosthesis of FIG. 56.

FIG. 58 shows the thin high tensile tether being pulled out of an end ofthe fully loaded endoluminal prosthesis of FIG. 56.

The drawings illustrate embodiments of the technology and are notlimiting. For clarity and ease of illustration, the drawings may not bemade to scale and, in some instances, various aspects may be shownexaggerated or enlarged to facilitate an understanding of particularembodiments.

DETAILED DESCRIPTION

As discussed above, there is a need for catheter systems for deploymentof endoluminal prostheses that can reliably and accurately deliver suchdevices to a wide variety of body lumen target sites within a patient.In order to achieve this, it may be desirable to configure cathetersystem embodiments to maintain control of an axial position of anendoluminal prosthesis during deployment in order to maintain accuracy.It may also be desirable to minimize frictional forces within thevarious components of catheter system embodiments such that the cathetersystem embodiments function readily even in difficult to access andtortuous anatomies. In addition, minimizing frictional forces may beimportant when accessing body lumen target sites that are spatiallyremote from a point of access to the patient's body. Various cathetersystem embodiments are discussed herein that may be directed toachieving one or more such desirable attributes. In addition, variousmethods of using such catheter systems or methods of preparing ormanufacturing such catheter systems are also discussed. With regard toterms used to describe the orientation of the various catheter systemsdiscussed herein, the term “distal” is used to describe a position ordirection away from a user of a catheter system and the term “proximal”is used to describe a position or direction towards a user of a cathetersystem. The same convention also applies to endoluminal prosthesescomponents of such catheter systems. Although it is common to describe a“proximal” end of endoluminal prosthesis devices as being that end whichis disposed towards a flow of blood of a patient, this convention is notadopted herein.

Referring to FIGS. 1-10, a catheter system 10 is shown that isconfigured to control an axial position of a self-expanding endoluminalprosthesis 12 during deployment. In particular, the catheter system 10for deploying the endoluminal prosthesis 12 in a body lumen 14 of apatient is shown which may include a flexible elongate chassis 16 havinga proximal end 18, a distal end 20, a distal section 22 and an overallcolumn strength configured for advancement of the chassis 16 through abody lumen 14 of a patient. In some cases, the elongate chassis 16 maybe configured for atraumatic passage through tortuous body lumens 14 ofa patient, such as tortuous arteries or veins of a patient'svasculature. The chassis may have any suitable configuration thatprovides both a sufficient flexibility in order to navigate a patient'sbody lumens 14 and structural strength in order to support the variousstructures secured thereto and functions carried out with the chassis16. In some cases, the chassis may include an elongate tubular structuremade from any suitable biocompatible polymer such as polyurethane,polytetrafluoroethylene (PTFE), polyethylene (PE), nylon, Pebax®,fluorinated ethylene propylene (FEP), polyimides, composite materials orthe like.

The self-expanding tubular endoluminal prosthesis 12 is shown disposedin a constrained state over the distal section of the chassis 16 withproximal axial displacement of the endoluminal prosthesis 12 beingrestricted by a plurality of extensions 24 that extend from the chassis16 through a distal end 26 of the endoluminal prosthesis 12. Theproximal axial displacement of the endoluminal prosthesis 12 may be sorestricted by one or more such extensions 24. Each extension 24 may be athin, flexible, resilient extension having a proximal end 28 which issecured in fixed relation to the elongate catheter chassis 16 and adistal end 30 which is disposed radially outward from an outside surface32 of the chassis 16 and distal of the proximal end 28 of the extension24. The fixation of the proximal end 28 relative to the chassis may befacilitated by a base structure such as a high strength cylinder ofmaterial that may or may not be made from the same material as theextension 24. Each of the extensions 24 may extend through a wall 34 ofthe distal end 26 of the endoluminal prosthesis 12 with the extension 24in a radially constrained state such that the extension 24 at leastpartially captures a distal segment 36 of the endoluminal prosthesis 12and restricts proximal displacement of the endoluminal prosthesis 12relative to the chassis 16 as shown in FIG. 2. For some embodiments, thecatheter system 10 may have 1 extension 24 to 10 extensions 24, morespecifically, 2 extensions 24 to 6 extensions 24, and even morespecifically, 3 extensions 24 to 4 extensions 24.

The catheter system 10 may optionally include a tubular outer sheath 38which is disposed over the endoluminal prosthesis 12 and chassis 16 andwhich includes an inner surface 40 that constrains the endoluminalprosthesis 12 in the constrained state. The inner surface 40 of theouter sheath may also be configured to radially restrain distal ends 30of the extensions 24 in a radially constrained state as shown in FIG. 2.Such a radially constrained state of the extensions 24 provides moreleverage for the extensions 24 to restrict proximal axial movement ofthe endoluminal prosthesis 12 because the radial constraint on thedistal ends 30 of the extensions 24 prevents them from pivoting in aproximal direction when proximal tension is applied to the endoluminalprosthesis 12. As such, for some embodiments, the extensions 24 may havedistal ends 30 that extend radially outward from the chassis 16 in arelaxed unconstrained state by a distance similar to a radius of theendoluminal prosthesis 12 to be deployed when that endoluminalprosthesis 12 is also in an unconstrained state. In some instances, anangle 41 that the flexible extensions 24 form with respect to alongitudinal axis 42 of chassis 16 may be about 5 degrees to about 50degrees with the extension 24 in a relaxed unconstrained state as shownin FIG. 8. The angle 41 of the flexible extensions 24 with respect tothe longitudinal axis 42 of the chassis may in some cases be defined bythe angle between the longitudinal axis 42 of the chassis 16 and a line44 extending from the proximal end 28 of the extension 24 to the distalend 30 of the extension 24 as shown in FIG. 8.

Because of the springy resilience of some extension embodiments 24, thedistal ends 30 of these extensions 24 may be easily passed through thewall 34 of the endoluminal prosthesis 12 when both the endoluminalprosthesis 12 and the extensions 24 are in a relaxed unconstrainedstate. Thereafter both the endoluminal prosthesis 12 and the extensions24 may be radially constrained by an inward radial force and held inthat constrained state by an inner surface 40 of the outer sheath 38 asshown in FIG. 2. In order to achieve both a proper flexibility andresilience as well as sufficiently strong bending moment in order toresists failing under an axial load from the endoluminal prosthesis 12during proximal retraction of the outer sheath 38, some extensionembodiments 24 may be made from a resilient high strength material suchas a metal alloy or composite material. For some embodiments, theextensions 24 may be made from or include superelastic nickel titaniumalloy. For some such embodiments, the extensions 24 may include atransverse cross section area of about 0.08 mm.sup.2 to about 1mm.sup.2. For some embodiments, the extensions 24 may have a length ofabout 4 mm to about 25 mm.

As shown in FIG. 7, the extension 24 lies substantially in a same planeas the longitudinal axis 42 of the chassis 16. In some cases, themeaning of the phrase substantially in the same plane may include lyingwithin a thickness of the extension 24 of lying in the same plane as thelongitudinal axis 42 of the chassis 16. For some embodiments, theplurality of extensions 24 is evenly distributed with respect tocircumferential orientation about the chassis 16. For example, for suchcatheter system embodiment 10 having extensions 24, the extensions 24would be spaced about 120 degrees apart from each other about thelongitudinal axis 42 of the chassis 16. In some instances, the extension24 may have an s-shape in the unconstrained relaxed state as shown inmore detail in FIG. 8. For the embodiment shown, a proximal mostdeflection 46 of the s-shape of the extension 24 extends away from thechassis as indicated by arrow 48 and a distal most deflection 50 of thes-shape of the extension 24 extends towards the chassis as indicated byarrow 52. The outward facing curvature of the proximal most deflection46 may be useful in order to provide a smooth rounded profile forpassage within a constraining tubular structure such as the outer sheath38 or everting sheath 172 discussed below. The proximal most deflection46 may also be useful for providing a gap between the outer surface 32of the chassis and the extensions 24 to accommodate the distal section36 of the endoluminal prosthesis which may be at least partiallymechanically captured by the extension so as to restrict proximal axialmovement of the endoluminal prosthesis 12. The optional distal mostdeflection 50 may be useful in some circumstances for loading theendoluminal prosthesis 12 and distal segments 36 thereof onto therespective extensions 24. The outwardly pointed direction of theproximal ends 28 of the extensions 24 may be useful to facilitatepenetration of the extensions 24 through the wall 34 of the endoluminalprosthesis 12 when both the extensions 24 and endoluminal prosthesis 12are in a relaxed unconstrained state.

For some embodiments, the distal segment 36 of the endoluminalprosthesis 12 captured by the extension 24 may include a high strengthstent element 54 of a self-expanding stent 56 of the endoluminalprosthesis 12 as shown in FIGS. 2 and 3. In some cases, the stentelement 54 captured by the extension 24 includes a crown section of thestent (not shown). A high strength stent element 54 may include aresilient and optionally superelastic material such as nickel titaniumalloy or the like.

For some embodiments, the chassis 16 may optionally include a guidewirelumen 58 to slidably house a guidewire 60 extending from the proximalend 18 of the chassis 16 to the distal end 20 of the chassis 16. In someinstances, the catheter system 10 may also include a nosecone 62 securedto a distal end 20 of the chassis 16. The nosecone 62 may include ashoulder portion 64 which is disposed within a distal end 66 of thetubular outer sheath 38 which may also be disposed over the endoluminalprosthesis 12 and chassis 16. The outer sheath 38 includes the innersurface 40 that at least partially radially constrains the endoluminalprosthesis 12 and extensions 24 in the constrained state. For some suchembodiments, referring specifically to FIGS. 13-16, the shoulder portion64 of the nosecone 62 may further optionally include one or moreelongate longitudinally oriented slots 68 which are configured to acceptthe distal end 30 of corresponding extensions 24 when the extensions 24are in the radially constrained state. Some embodiments of theselongitudinally oriented slots 68 may be disposed so as to besubstantially parallel to and lie substantially in the same plane as thelongitudinal axis 42 of the chassis 16. The longitudinally orientedslots 68 in the nosecone 62 may be useful in some instances forstabilizing the distal ends 30 of the one or more extensions 24 whendisposed in the radially constrained state. The distal ends 30 of theextensions may lie in the slots 68 between the nosecone 62 and the innersurface 40 of the outer sheath 38. The slots 68 may, in some instances,make a radial depth of about 0.2 mm to about 3 mm and a circumferentialwidth of about 0.2 mm to about 3 mm. For some embodiments, the slots mayhave an axial length of about 1 mm to about 10 mm and may in some casesextend all or most of an axial length of the shoulder portion 64.

In some cases, the tubular endoluminal prosthesis 12 may be a tubularstent graft including at least one layer of thin, compliant material 70secured to the self-expanding stent 56. For some of these embodiments,the thin compliant material 70 may include nylon mesh, PTFE, ePTFE orthe like. In some instances, the stent graft 12 may be a fully stentedstent graft as shown in FIG. 9 wherein the helical resilient andundulating stent 56 which is secured to the tubular graft material 70extends all the way from a distal end 26 of the stent graft to aproximal end of the stent graft. For some embodiments, the endoluminalprosthesis may include a stent 56 made from a high strength superelasticmetal alloy such as a nickel titanium or the like.

In use, referring back to FIGS. 1-5, a method embodiment for deployingthe endoluminal prosthesis 12 in the body lumen 14 of the patient mayinclude advancing the catheter system 10 into the body lumen 14 of thepatient until the endoluminal prosthesis 12 is disposed at a treatmentsite 74. In some cases, it may be desirable to advance the cathetersystem 10 to the treatment site over the guidewire 60 which may bepreviously disposed across a treatment site 74, which may be moved alongahead of the catheter system 10 in a step by step approach or by anyother suitable method. Suitable treatment sites 74 for any of thecatheter system embodiments 10 and method embodiments discussed hereinmay include a wide variety of indications such as treatment of vasculardefects such as an aneurysm (not shown) or the like or any othersuitable indication wherein an endovascular prosthesis 12 may beindicated. In addition, suitable treatment sites 74 may include healthybody lumen sections or substantially healthy body lumen sections thatare adjacent to vascular defects. Deployment of endoluminal prosthesesin such healthy body lumen sections may be desirable in some cases inorder to extend a previously deployed endoluminal prosthesis 12 or forany other suitable indication.

An outer constraint, such as the outer constraint of the outer sheath38, may then be removed from the endoluminal prosthesis 12 while theextensions 24 prevent proximal axial movement of the endoluminalprosthesis 12 relative to the chassis 16 due to frictional forcesbetween the outer surface 76 of the endoluminal prosthesis 12 and theinner surface 40 of the outer sheath 38 during proximal retraction ofthe outer sheath 38. In such cases as shown in FIG. 3, the outerconstraint may be removed by proximally retracting the outer sheath 38of the catheter system 10 which both releases the radial constraint ofthe outer sheath 38 on the endoluminal prosthesis 12 but also imposes anaxial force in a proximal direction on the endoluminal prosthesis 12 dueto the frictional interaction between the inner surface 40 of the outersheath 38 and outside surface 76 of the endoluminal prosthesis 12. Aninner transverse dimension of the outer sheath 38 will typically be lessthan an outer transverse dimension of the endoluminal prosthesis 12 in arelaxed unconstrained state. The extensions 24 may each include theproximal end 28 which is secured in fixed relation to the elongatecatheter chassis 16 and the distal end 30 which is disposed radiallyoutward from the outside surface 32 of the chassis 16 and distal of theproximal end 28 of the extension 24 as discussed above. Each of the oneor more extensions 24 may also extend through the wall 34 of the distalend 26 of the endoluminal prosthesis 12 with the distal end 30 of theextension 24 held in a radially constrained state by the inner surface40 of the outer sheath 38, also as discussed above. The extensions 24are so constrained such that each of the one or more extensions 24 atleast partially captures the respective distal segment 36 of theendoluminal prosthesis 12. As the outer constraint is removed, theendoluminal prosthesis 12 is then allowed to self-expand such that anoutside surface of the endoluminal prosthesis 12 contacts an insidesurface 78 of the patient's body lumen 14 as shown in FIG. 3. Thechassis 16 and one or more extensions 24 may then be proximallyretracted as a unit such that each of the extensions 24 slide axiallythrough a respective perforation in the wall 34 of the distal end 26 ofthe endoluminal prosthesis 12 and the endoluminal prosthesis 12 isallowed to fully deploy and engage the inside surface 78 of the bodylumen 14 of the patient as shown in FIG. 4.

Referring to FIGS. 11 and 12, an embodiment of an elongate chassis 80that may be used in any suitable catheter system embodiment 10 discussedherein is shown that includes a tubular member 82 of flexible, resilientmaterial that has a plurality extensions 84 configured for endoluminalprosthesis retention cut directly from the tubular member 82 of theelongate chassis 80. Such an “as cut” configuration of the elongatechassis 80 may be made from any suitable high strength resilientmaterials such as stainless steel, and shape memory materials such asnickel titanium alloy and the like. For shape memory embodiments, theextensions 84 may be heat set into any of the shapes and configurationsas discussed above with regard to the other extension embodimentsincluding the same or similar length, cross section area, s-shapeconfiguration angle formed with respect to the longitudinal axis 42 ofthe chassis 16, 80 etc. The extensions 84 may be cut from the tubularchassis 80 by any suitable method including laser cutting, water jetcutting, wire EDM or the like.

Referring to FIGS. 17 and 18, an embodiment of an elongate chassis 16including substantially rigid extensions 86 configured for endoluminalprosthesis retention for use in catheter system embodiments 10 fordeploying an endoluminal prosthesis 12 in a body lumen 14 of a patientis shown. The elongate chassis 16 may have one or more such rigidextension embodiments 86 secured in a fixed relation thereto. The rigidextension embodiments 86 may include a proximal end 88 which is securedin fixed relation to the elongate catheter chassis 16 and a distal end90 which is disposed radially outward from an outside surface 32 of thechassis 16 and distal of the proximal end 88 of the extension 86. Suchsubstantially rigid extension embodiments 86 may extend through arespective perforation in the wall 34 of a distal end 26 of theendoluminal prosthesis 12 such that the extensions 86 at least partiallycapture the distal segment 36 of the endoluminal prosthesis 12 andrestrict proximal displacement of the endoluminal prosthesis 12 relativeto the chassis 16. In this sense, the rigid extensions 86 may functionsimilarly to the extensions 24 discussed above. The term substantiallyrigid used in this context herein is meant to include extensions 86 thedistal ends 90 of which are not deflected or displaced during normal useby an amount more than about 1 mm with respect to the chassis 16 due toforces imposed by the endoluminal prosthesis 12 on the extensions 86during deployment of the endovascular graft 12. The extensionembodiments 86 may otherwise have the same or similar lengths as thelengths discussed above with regard to the flexible resilient extensionembodiments 24. The distal ends 90 of the substantially rigid extensions86 may be disposed with a gap 92 between distal ends 90 of theextensions 86 and the outside surface 32 of the chassis 16 of about 0.5mm to about 5 mm. The substantially rigid extensions 86 may be made fromany suitable high strength material or materials including metal andmetal alloys such as stainless steel, nickel titanium, compositematerials or the like.

Referring to FIGS. 19-22, a catheter system embodiment 100 for deployingan endoluminal prosthesis 12 in a body lumen 14 of a patient is shown.The catheter system includes the flexible elongate chassis 16 having aproximal end 18, a distal end 20, a distal section 22 and an overallcolumn strength sufficient for advancement of the chassis through a bodylumen 14 of a patient. Such a catheter system 100 may also include aself-expanding tubular endoluminal prosthesis 12 disposed in aconstrained state over the distal section 22 of the chassis 16. Inaddition, the catheter system 100 may include one or more thin,flexible, axial belts 102 with each axial belt 102 having a fixed end104 which is secured in fixed relation to the elongate catheter chassis16 and a free end 106 which is disposed opposite the fixed end 104. Forsuch catheter system embodiments, each axial belt 102 may form a loop108 that extends proximally from the fixed end 104 and free end 106through a distal segment 36 of a wall 34 of the endoluminal prosthesis12. The free end 106 of each axial belt 102 may be releasably secured infixed relation to the chassis 16 with a circumferential belt 110 whichis disposed about the chassis 16 and free ends 106. The circumferentialbelt 110 may be configured to apply an inward radial force on the freeend 106 of each axial belt 102 sufficient to releasably secure each freeend 106 in fixed relation to the chassis 16. The inward radial force ofthe circumferential belt may be generated by tension of circumferentialbelt 110 squeezing the free ends 106 against the outside surface 32 ofthe chassis 16. In such a fixed relation, the loop is configured tocapture the distal segments 36 of the endoluminal prosthesis 12 aroundwhich the loops 108 are disposed so as to restrict proximal displacementof the endoluminal prosthesis 12 relative to the chassis 16.

For some such embodiments, the circumferential belt 110 may bereleasably secured around the free ends 106 and chassis 16 in atensioned state by a trigger wire 112 which passes through looped ends118 of the circumferential belt 110. Such a trigger wire 112 may extendaxially along or within the chassis 16 from the circumferential belt 110to the proximal end 18 of the chassis 16 and ultimately to a deploymenthandle 114 of a proximal adapter 116. The deployment handle 114 may beactuated so as to apply axial translation of the trigger wire 112 in aproximal direction and retract the trigger wire from the end loops 118.In some cases, it may be desirable for the trigger wire 112 to havesufficient stiffness in order to keep end loops 118 of thecircumferential belt 110 in fixed relation to each other until thetrigger wire 112 is withdrawn while still maintaining sufficientflexibility to be advanced through tortuous body lumens 14 of thepatient. Some trigger wire embodiments 112 may be made from highstrength resilient flexible materials including metals and metal alloyssuch as nickel titanium alloy including superelastic nickel titaniumalloy as well as stainless steel, composite materials and the like. Insome cases, the trigger wire 112 may have a cross section area of about0.002 mm.sup.2 to about 0.06 mm.sup.2, more specifically, about 0.04mm.sup.2 to about 0.05 mm.sup.2.

For those catheter system embodiments that include a plurality of axialbelts 102, the plurality of axial belts 102 may be evenly distributedabout the chassis 16 with respect to circumferential orientation aboutthe chassis 16. For some embodiments, the one or more axial belts 102may have a length of about 10 mm to about 25 mm. For some embodiments,each of the one or more axial belts 102 may have a transverse crosssection area of about 0.002 mm.sup.2 to about 0.16 mm.sup.2, morespecifically, about 0.05 mm.sup.2 to about 0.09 mm.sup.2. In some cases,the catheter system 100 may include 1 axial belt 102 to 10 axial belts102, more specifically, 2 axial belts 102 to 6 axial belts 102 and evenmore specifically, 3 axial belts 102 to 4 axial belts 102. In somecases, the axial belt 102 and releasable circumferential belt 110 may bemade from any suitable high tensile flexible material including solidwires or braided or stranded filaments of metals including metal alloyssuch as stainless steel, superelastic nickel titanium as well as solid,braided or stranded filaments of high strength polymers such as nylon,aramid fibers and the like.

In some cases, a respective distal segment 36 of the endoluminalprosthesis 12 may be captured by the loop 108 of each of the one or moreaxial belts 102. Each distal segment 36 may include the high strengthstent element 54 of the self-expanding stent 56 of the endoluminalprosthesis 12. In addition, the stent element 54 captured by each of theloops of the one or more axial belts 102 may include a crown section ofthe stent 56 (not shown). The high strength stent element 54 may includea resilient and optionally superelastic material such as nickel titaniumalloy or the like.

For some embodiments, the chassis 16 may optionally include a guidewirelumen 58 extending from the proximal end 18 of the chassis 16 to thedistal end 20 of the chassis 16. In some instances, the catheter system100 may also include a nosecone 62 secured to the distal end 20 of thechassis 16. The nosecone may have a shoulder portion 64 which isdisposed within a distal end 66 of the tubular outer sheath 38. Theoptional tubular outer sheath 38 which is disposed over the endoluminalprosthesis 12 and chassis 16 may include an inner surface 40 that atleast partially radially constrains the endoluminal prosthesis 12 in theconstrained state.

In some cases, the tubular endoluminal prosthesis embodiments 12discussed herein may be a tubular stent graft including at least onelayer of thin, compliant material 70 secured to the self-expanding stent56 as shown in FIGS. 9 and 10. For some of these embodiments, the thincompliant material 70 may include nylon mesh, PTFE, ePTFE or the like.In some instances, the stent graft 12 may be a fully stented stent graftas shown in FIG. 9 wherein the helical resilient and undulating stent 56which is secured to the tubular graft material 70 extends all the wayfrom a distal end 26 of the stent graft 12 to a proximal end 72 of thestent graft 12.

In use, referring to FIGS. 23-25, a method for deploying the endoluminalprosthesis 12 in the body lumen 14 of a patient may include advancingthe catheter system 100 into the body lumen 14 of the patient until theendoluminal prosthesis 12 of the catheter system is disposed at atreatment site 74 as shown in FIG. 23. In some cases, it may bedesirable to advance the catheter system 100 to the treatment site 74over the guidewire 60 which may be previously disposed across atreatment site 74, which may be moved along ahead of the catheter system100 in a step by step approach or by any other suitable method. An outerconstraint, such as the outer sheath 38, may be removed from theendoluminal prosthesis 12 while the axial belts 102 restrict proximalaxial movement of the endoluminal prosthesis 12 relative to the chassisas shown in FIG. 24. Removal of the outer constraint on the endoluminalprosthesis 12 may include proximal retraction of the outer sheath 38 asindicated by arrow 120 in FIG. 23. In some cases, the outer sheath 38may be proximally retracted by applying proximal tension to theretraction handle 67 relative to the chassis 16. As discussed above, theaxial belts 102 may include the fixed end 104 which is secured in fixedrelation to the elongate catheter chassis 16 and the free end 106 whichis disposed opposite the fixed end 104. The axial belts 102 form theloops 108 that extend proximally from the fixed ends 104 and free ends106 through the distal segment 36 of the wall 34 of the endoluminalprosthesis 12. The free ends 106 of the axial belts 102 are releasablysecured in fixed relation to the chassis 16 with the circumferentialbelt 110 which is disposed about the chassis 16 and free ends 106. Theloops 108 of each of the one or more axial belts 102 capture andrestrict axial movement in a proximal direction of the respective distalsegments 36 of the endoluminal prosthesis 12. The endoluminal prosthesis12 may be allowed to self-expand by removal of the constraint, such asby proximal retraction of an outer sheath 38, such that an outsidesurface 76 of the endoluminal prosthesis 12 contacts an inside surface78 of the patient's body lumen 14. The tension of the circumferentialbelt 110 and resulting inward radial force may then be released from theone or more axial belts 102 by proximal retraction of the trigger wire112 from the end loops 118 of the circumferential belt 110. The freeends 106 of the axial belts 102 are thereby released from the distalsegments 36 of the endoluminal prosthesis 12. In this way, theendoluminal prosthesis 12 is allowed to further self-expand and be fullydeployed and engage the inside surface 78 of the body lumen 14. Thechassis 16 and one or more axial belts 102 may then be proximallyretracted such that the axial belts 102 are withdrawn from respectiveperforations in the wall 34 of the distal end of the endoluminalprosthesis 12 as shown in FIG. 25.

Referring to FIG. 26, another embodiment of a catheter system 126 isshown which has an endoluminal prosthesis restraint system which issimilar to that of the catheter system 100 of FIGS. 19-22. However,instead of each loop 108 of each axial belt 102 extending from the fixedend 104 around the distal segment 36 and back to the free end 106, as isthe case with catheter system 100 of FIGS. 19-25, the axial belts 128 ofthe catheter system embodiment 126 of FIG. 26 extend distally from afixed end 130 which is secured to the chassis 16, through a respectiveperforation in the wall 34, around a distal segment 36 of theendovascular prosthesis 12 and then to a free end 132. The free ends 132may be similarly releasably secured in fixed relation to the chassis 16with a circumferential belt 110 and trigger wire 112 arrangement withthe same or similar arrangement to that of the catheter systemembodiment 100 of FIGS. 19-22 with the same or similar features,dimensions and materials.

Referring to FIGS. 27-29, a catheter system 140 for deploying anendoluminal prosthesis in a body lumen of a patient includes a flexibleelongate chassis 16 having a proximal end 18, a distal end 20, a distalsection 22 and an overall column strength sufficient for advancement ofthe chassis 16 through a body lumen 14 of a patient. Such a cathetersystem 140 may also include a self-expanding tubular endoluminalprosthesis 12 disposed in a constrained state over the distal section 22of the chassis 16. In addition, the catheter system 140 may include aplurality of axial release wires 142, with each axial release wire 142having a proximal end, a distal end 144 and a distal section 146. Thedistal section 146 of each release wire 142 may extend through a distalsegment 36 of a wall 34 of the endoluminal prosthesis 12 with the distalsection 146 releasably secured in fixed relation to a pair of axiallyspaced bushings, including a proximal most bushing 148 and a distal mostbushing 150. The bushings 148, 150 are secured to and extend radiallyoutward from the chassis 16. Such a structure may be configured so as toform a loop structure 152 having a continuous enclosed structure formedbetween the distal section 146, the axially spaced bushings 148, 150 andan outside surface 32 of the chassis 16, such that this loop structure152 releasably captures s respective distal segment 36 of theendoluminal prosthesis 12 and restricts proximal displacement of theendoluminal prosthesis 12 relative to the chassis 16. This configurationmay also restrict outward radial displacement of the distal segments 36which are captured by the respective loop structures 152.

For some embodiments, the release wires 142 may be releasably secured tothe spaced bushings 148, 152 in a configuration wherein the releasewires 142 are disposed through a longitudinal lumen 154 of the proximalmost bushing 148 and a corresponding longitudinal lumen 156 of thedistal most bushing 150. In some cases, it may be desirable for thelongitudinal lumens 154, 156 of the bushings 148, 150 to have an innerdiameter with a substantially close fit to an outside surface 158 of therelease wire 142 disposed therein. In these cases, the substantiallyclose fit of the longitudinal lumens 154, 156 may provide additionalradial support and stability to the release wire 142 disposed therein.In some cases, corresponding longitudinal lumens 154, 156 of theproximal most bushing 148 and distal most bushing 150 may be coaxial orotherwise aligned with each other. In some cases, the spacing andconfiguration of the bushings 148, 150 and longitudinal lumens 154, 156may be important for the performance of the catheter system 140. Forsome embodiments, the spaced bushings 148, 150 may have an axial lengthof about 2 mm to about 15 mm, more specifically, about 5 mm to about 10mm and an outer diameter of about 2 mm to about 6 mm, more specifically,about 2 mm to about 3.5 mm. A longitudinal gap between a distal end ofthe proximal most bushing 148 and a proximal end of the distal mostbushing 150 may be about 4 mm to about 16 mm and a gap 160 between thelongitudinal lumens 154, 156 of the spaced bushings 148, 150 and outsidesurface 32 of the chassis 16 may be about 0.5 mm to about 5 mm in somecases.

For some embodiments, the plurality of axial release wires 142 may beevenly distributed with respect to circumferential orientation about thechassis 16 and spaced bushings 148, 150. Such release wires 142 mayextend axially along or within the chassis 16 from the spaced bushings148, 150 to the proximal end 18 of the chassis 16 and be coupled to adeployment handle, such as deployment handle 114 disposed on a proximaladapter 116 shown in FIG. 19. In some cases, it may be desirable for therelease wires 142 to have sufficient stiffness in order to keep distalsegments 36 of the endoluminal prosthesis 12 in fixed relation to thechassis 16 until the release wires 142 are withdrawn by proximalretraction from the handle 114 disposed at a proximal adapter 116 of thecatheter system 140. However, the release wires 142 should stillmaintain sufficient flexibility to be advanced through tortuous bodylumens 14 of the patient. Some release wire embodiments 142 may be madefrom high strength resilient flexible materials including metals andmetal alloys such as nickel titanium alloy including superelastic nickeltitanium alloy as well as stainless steel, composite materials and thelike. In some cases, the release wires 142 may have a cross section areaof about 0.04 mm.sup.2 to about 0.06 mm.sup.2. In some cases, thecatheter system 140 may have 2 axial release wires 142 to 10 axialrelease wires 142, more specifically, 2 axial release wires 142 to 6axial release wires 142, and even more specifically, having 3 axialrelease wires 142 to 4 axial release wires 142.

In some cases, the respective distal segments 36 of the endoluminalprosthesis 12 captured by the release wires 142 may include a highstrength stent element 54 of a self-expanding stent 56 of theendoluminal prosthesis 12. In addition, the stent element 54 captured byeach of the release wires 142 may include a crown section of the stent56. A high strength stent element 54 may include a resilient andoptionally superelastic material such as nickel titanium alloy or thelike.

For some embodiments, the chassis 16 may optionally include a guidewirelumen 58 extending from the proximal end 18 of the chassis 16 to thedistal end 20 of the chassis 16. In some instances, the catheter system140 may also include a nosecone 62 secured to the distal end 20 of thechassis 16, the nosecone 62 including a shoulder portion 64 which may bedisposed within a distal end 66 of a tubular outer sheath 38. An innersurface 40 of the optional outer sheath 38 may be disposed over theendoluminal prosthesis and chassis and at least partially radiallyconstrain the endoluminal prosthesis in the constrained state.

In some cases, the tubular endoluminal prosthesis 12 may be a tubularstent graft including at least one layer of thin, compliant material 70secured to the self-expanding stent 56. For some of these embodiments,the thin compliant material 70 may include nylon mesh, PTFE, ePTFE orthe like. In some instances, the stent graft 12 may be a fully stentedstent graft as shown in FIG. 9 wherein the helical resilient andundulating stent 56 which is secured to the tubular graft material 70extends all the way from the distal end 26 of the stent graft 12 to theproximal end 72 of the stent graft 12.

In use, as shown in FIGS. 28 and 30, deployment of the endoluminalprosthesis 12 may begin with proximal retraction of the optional outersheath 38 by applying axial tension to the retraction handle 67 which issecured to the proximal end 69 of the outer sheath 38 as shown in FIG.19. During proximal retraction of the outer sheath 38, proximaldisplacement of the endoluminal prosthesis 12 is restricted by the loopstructures 152 which mechanically capture respective distal segments 36of the endoluminal prosthesis 12. As discussed above, a proximal axialforce may be generated on the endoluminal prosthesis during retractionof the outer sheath 38 due to frictional engagement between the outersurface 76 of the endoluminal prosthesis 12 and the inner surface 40 ofthe outer sheath 38. The frictional engagement may be due to the outwardradial force of the radially constrained self-expanding stent 56 of someembodiments of the endoluminal prosthesis pushing the outside surface 76against the inner surface 40 of the outer sheath 38.

Once the outer sheath 38 has been proximally retracted, the releasewires 142 may then be proximally retracted from the respectivelongitudinal lumens 154, 156 of the spaced bushings 148, 150, or atleast the longitudinal lumens 156 of the distal most bushing 150 asshown in FIG. 28 may be carried out. Once the release wires 142 havebeen disengaged from at least the distal most bushing 150 and distalsegments 36 of the endoluminal prosthesis 12, the endoluminal prosthesis12 will be allowed to self-expand and engage an inside surface 78 of thebody lumen 14 of the patient as shown in FIG. 30. Prior to proximalretraction of the release wires 142, the loop 152 formed between therelease wires 142, spaced bushings 148, 150 and outside surface 32 ofthe chassis 16 serves to restrict axial movement in a proximal directionof the endoluminal prosthesis 12 due to frictional forces imposed on theendoluminal prosthesis 12 by proximal retraction of the optional outersheath 38 at the initiation of the deployment process. In this way, theaxial position of the endoluminal prosthesis 12 is maintained relativeto the chassis 16 and body lumen 14 during the deployment process.

Referring to FIGS. 31-41, some embodiments of a catheter system 170 fordeploying an endoluminal prosthesis 12 in a body lumen 14 of a patientmay include an optional flexible elongate chassis 16 having a proximalend 18, a distal end 20, a distal section 22, a longitudinal axis 42,and a column strength configured for advancement of the chassis 16through a body lumen 14 of a patient. Such a catheter system 170 mayalso include a self-expanding tubular endoluminal prosthesis 12 disposedin a constrained state at a distal section 22 of the chassis 16. Thecatheter system includes a tubular everting sheath 172 which has aninner section 174. The inner section includes a first diameter, a fixedend 176 which is secured in fixed relation to the chassis 16 and anendoluminal prosthesis section 178 that is disposed over and radiallyconstrains the endoluminal prosthesis 12 in the constrained state. Thefixed end 176 may be disposed at the distal end of the inner section andin some cases, the inner section 174 may be secured in fixed relation tothe chassis 16 at a position that is adjacent a proximal end of theendoluminal prosthesis section 178. The endoluminal prosthesis section178 is generally disposed at a distal end of the inner section 174opposite the fixed end 176 and adjacent the distal section 22 of thechassis 16. The inner section 174 joins an outer section 180 at atransition point where there may optionally be a transition in thediameter, thickness and/or material of the everting sheath 172. A firstdiameter of the inner section 174 is indicated by arrows 179 shown inFIG. 38.

The tubular everting sheath 172 includes also the outer section 180 thatis everted back over the endoluminal prosthesis section 178 of the innersection 174 and may also be everted back over some or all of theremainder of the inner section 174 that is proximal of the endoluminalprosthesis section 178. The outer section 180 may include a retractionend 182 and a second diameter which is larger than the first diameter ofthe inner section 174 such that the outer section 180 is readilyslideable over the inner section 174 during retraction of the retractionend 182 and eversion of the everting sheath 172. The retraction end 182is secured to a retraction handle 186 that may be used to apply proximalaxial tension to the outer section 180 relative to the chassis 16 andinner section 174 in order to pull the outer section 180 back over theinner section 174 to evert the everting sheath 172. As such, it may bedesirable in some cases for the optional chassis 16 to have sufficientcolumn strength to resist the axial tension applied to the retractionend 182 of the outer section 180 during eversion of the everting sheath172. The second diameter of the outer section 180 is indicated by arrows181 shown in FIG. 38.

For catheter system embodiments 170 that include the stepped ormulti-diameter everting sheath 172, the diameter of the outer section180 may be greater than the first diameter of the inner section 174 byan amount of at least a wall thickness, indicated by arrows 184 shown inFIG. 38, of the outer section 180 of the tubular everting sheath 172 insome cases. For some embodiments, the thickness 184 of the wall of theeverting sheath may be about 0.05 mm to about 2 mm. This dual diameterarrangement may be useful in order to reduce friction and tensile forceson the outer section 180 required to evert the tubular everting sheath172. For some embodiments, a lubricating material 175 disposed betweenthe inner section 174 and outer section 180 as shown in FIG. 35 may beused to reduce friction between these sections 174, 180 during eversion.Suitable lubricating materials for the lubricating material 175 mayinclude liquids, pastes, gels, including hydrogels as well as tubularstructures formed from lubricious materials.

Some embodiments of the everting sheath may also include a PTFE materialthat has a closed cell microstructure with no distinct fibrilsinterconnecting adjacent nodes such that the outer section is readilyslideable over the inner section due at least in part to the lubriciousand supple nature of this type of material. Catheter system embodimentsthat include an everting sheath having a PTFE material with a closedcell microstructure with no distinct fibrils may also optionally beconfigured without the dual diameter everting sheath wherein the innersection 174 has a different diameter than the outer section 180. Asdiscussed above, various components of the catheter systems and/orendoluminal prosthesis devices discussed herein may include a type ofPTFE material that is produced by a wet stretching method or the likethat yields a closed cell microstructure having no distinct fibrilsinterconnecting adjacent nodes as described in commonly owned U.S. Pat.No. 8,728,372, filed by J. Humphrey et al. on Oct. 29, 2010, titled“PTFE Layers and Methods of Manufacturing”, which is hereby incorporatedby reference herein in its entirety.

Manufacture of these types of specialized PTFE materials may be carriedout by any suitable method. Such PTFE materials may be produced bycompounding PTFE resin powder with a lubricant material, stretchingagent, or combination thereof, and then extruding that compoundedmaterial through an extruder such as a ram extruder. The extrudate maythen be calendered in order to thin and mechanically work the extrudate.After calendering, one side or both sides of the calendered PTFE layerare sprayed with an isoparaffin-based stretching agent at a prescribedtemperature so that the PTFE film or layer is flooded and fullysaturated through the thickness of the PTFE layer. The saturated,calendered PTFE layer may then be stretched in a direction that issubstantially orthogonal to the calendering direction by a tenteringmachine to reduce a thickness of the PTFE layer and form a stretchedPTFE layer. The stretched PTFE layer may have a thickness of about0.00005 inch to about 0.005 inch; specifically, the stretched PTFE layermay have a thickness of about 0.0002 inch to about 0.002 inch. The PTFElayer typically is tentered or stretched at an elevated temperatureabove the glass transition temperature, specifically, from about80.degree. F. to about 100.degree. F., more specifically, about85.degree. F. to about 95.degree. F. Wet tentering with the stretchingagent allows the PTFE layer to be thinned without creating substantialporosity and fluid permeability in the stretched PTFE layer. While thestretched PTFE layer will have porosity, its porosity and pore sizetypically will not be large enough to be permeable to liquids, and oftenwill be small enough to have substantially no fluid permeability. Inaddition, the stretched PTFE layer embodiment does not have theconventional node and fibril microstructure but instead has a closedcell microstructure in which boundaries of adjacent nodes are directlyconnected with each other. The fluid-impermeable stretched PTFE film orlayer typically may have a density from about 0.5 g/cm.sup.3 to about1.5 g/cm.sup.3, but it may have a larger or smaller density for someembodiments. In addition, with regard to all of the methods ofprocessing layers of PTFE discussed above, any of the PTFE layersproduced by these methods may also be sintered at any point in the aboveprocesses in order to substantially fix the microstructure of the PTFElayer. A typical sintering process may be to expose the PTFE layer to atemperature of about 350.degree. C. to about 380.degree. C. for severalminutes; specifically, about 2 minutes to about 5 minutes. The variousmethods discussed above may be used to produce PTFE layers having avariety of desirable properties. Scanning electron microscope (SEM)images of such materials show a generally closed cell microstructurethat is substantially free of the conventional node and fibrilmicrostructure commonly seen in expanded PTFE layers. Embodiments of thePTFE film may have low fluid-permeability, or no or substantially nofluid-permeability. One or more of PTFE layer may be used as a barrierlayer to prevent a fluid such as a liquid or gas from permeating orescaping therethrough. At a magnification of 20,000, the microstructureof the stretched PTFE layer resembles a pocked-like structure thatincludes interconnected high density regions and pockets or poresbetween some of the high density regions. The PTFE film may beconsidered to have a closed cell network structure with interconnectedstrands connecting high density regions in which a high density regiongrain boundary is directly connected to a grain boundary of an adjacenthigh density region. Unlike conventional expanded PTFE (“ePTFE”) whichtypically has a substantial node and fibril microstructure that isdiscernable when viewed at a SEM magnification of 20,000, such a PTFElayer lacks the distinct, parallel fibrils that interconnect adjacentnodes of ePTFE and has no discernable node and fibril microstructurewhen viewed at a SEM magnification of 20,000. The closed cellmicrostructure of the PTFE layer provides a layer having low orsubstantially no fluid permeability that may be used as “a barrierlayer” to prevent liquid from passing from one side of the PTFE layer tothe opposite side. Though such a PTFE film or layer is configured tohave low or substantially no fluid permeability, the PTFE layernonetheless has a porosity. The PTFE layer typically has an averageporosity from about 20% to about 80%, and specifically from about 30%and about 70%. In one embodiment, such a PTFE film has a porosity ofabout 30% to about 40%. In another embodiment, such a PTFE layer has aporosity of about 60% to about 70%. Porosity as described in thesefigures is meant to indicate the volume of solid PTFE material as apercentage of the total volume of the PTFE film. An average pore size inthe PTFE layer may be less than about 20 microns, and specifically lessthan about 0.5 micron. In one embodiment, such a PTFE layer has anaverage pore size of from about 0.01 micron to about 0.5 micron. As canbe appreciated, if tissue ingrowth is desired, the PTFE film may have anaverage pore size of greater than about 6.0 microns. As described below,depending on the desired properties of the resultant PTFE layer,embodiments of methods may be modified so as to vary the averageporosity and average pore size of the PTFE film in a continuum from 10microns to 50 microns down to substantially less than about 0.1 micron.In some cases, such a PTFE layer may have a density from about 0.5g/cm.sup.3 to about 1.5 g/cm.sup.3, and specifically from aboutg/cm.sup.3 to about 1.5 g/cm.sup.3. While the density of the PTFE filmis typically less than a density for a fully densified PTFE layer (e.g.,2.1 g/cm.sup.3), if desired, the density of the PTFE layer may bedensified to a higher density level so that the density of the PTFElayer is comparable to a fully densified PTFE layer. Such a PTFE filmembodiment may have an average thickness that is less than about 0.005inch, specifically from about 0.00005 inch to about 0.005 inch, and morespecifically from about 0.0001 inch to about 0.002 inch.

In some cases, the everting sheath 172 or sections 174, 180 thereof mayinclude a layered tubular structure including a plurality of layers187A, 187B, 187C of thin pliable material which are secured together asshown in FIG. 39. In addition, an everting sheath 172 including a singlelayer of material or any section of an everting sheath formed from aplurality of layers 187 may include for example, any suitable pliable,low friction material such as PTFE, ePTFE, the PTFE having a closed cellmicrostructure with no distinct fibrils interconnecting adjacent nodesas discussed above or any suitable material.

FIG. 39 illustrates a portion of the outer section 180 of the evertingsheath 172 that includes a plurality of layers of material. For theembodiment shown, the everting sheath includes three separate anddistinct layers of material that may optionally be fused or bondedtogether over an entire surface or partial surface of each of the layers187A, 187B, 187C. Each of the layers may include the same materials ordifferent materials. The number of layers 187 may be varied to achievedesired properties of the everting sheath 172. For some embodiments, theeverting sheath may have 1 layer to 10 layers of material, morespecifically, 2 layers to 6 layers, and even more specifically, 3 layersto 4 layers of material. In some instances, for everting sheathembodiments 172 that include multiple layers, one or more of the layersmay include ePTFE that may or may not be anisotropically oriented andone or more layers of PTFE that has a closed cell microstructure with nodistinct fibrils interconnecting adjacent nodes as discussed above.

In some cases, for everting sheath embodiments 172 that include PTFEmaterial and particularly ePTFE material, any of the one or more layersof the everting sheath material may include an anisotropic orientationthat provides a greater strength in a first direction relative to asecond direction perpendicular to the first direction. For example, alayer of ePTFE material that has an anisotropic orientation providinggreater strength in a longitudinal direction may be of particular usefor the outer section 180 of the everting sheath 172 which is subjectedto longitudinal tensile forces during eversion of the everting sheath172. For other embodiments, a layer of ePTFE material that has ananisotropic orientation providing greater strength in a circumferentialdirection may be of particular use for the inner section 174 of theeverting sheath 172 which is subjected to outward radial forces of theconstrained self-expanding endoluminal prosthesis 12 disposed in theendoluminal prosthesis section 178 of the inner section 174. Any desiredcombination of these anisotropic materials may be used for the layers ofmultiple layer everting sheath embodiments 172.

For some embodiments of the catheter system 170, any of the evertingsheath embodiments 172 may further include one or more thin, elongate,high tensile retraction tethers 188 disposed between adjacent layers 187of the layered tubular structure of the everting sheath 172 andextending longitudinally along the endoluminal prosthesis section 178and outer section 180 of the everting sheath 172 as shown in FIGS. 39and 40. For single layer everting sheath embodiments 172, suchretraction tethers 188 may be secured to either surface of the evertingsheath. In some cases, the one or more retraction tethers may behelically wound about a tubular structure of the everting sheath 172 asshown in FIG. 40. For the embodiment shown in FIG. 39, the retractiontether 188 is disposed between the first layer 187A and the second layer1876. The third layer 187C is secured to the second layer 187B. Theretraction tether 188 may also be disposed between the second layer 187Band the third layer 187C. For 4 layer everting sheath embodiments (notshown) the retraction tether may be disposed between a first layer andsecond layer, between the second layer and third layer, or between thethird layer and a fourth layer. The retraction tethers 188 may be usefulfor reinforcing and/or gripping the everting sheath 172 during theeversion process. As such, it may be desirable to secure a retractionend of the retraction tethers 188 to the retraction handle 186.

In some cases, the everting sheath 172 of the catheter system 170 mayinclude an optional integral funnel section 190 disposed at theretraction end 182 of the outer section 180 of the everting sheath 172as shown in FIG. 40. The funnel section 190 may be useful for bothloading the endoluminal prosthesis 12 into the everting sheath 172 aswell as facilitating relative movement between the outer section 180 andinner section 174 during eversion. In some cases, the funnel section 190may have an inclusive funnel angle as indicated by arrow 192 in FIG. 40,of 10 degrees to 40 degrees. For some embodiments, the funnel section190 may have a major diameter, indicated by arrow 194 in FIG. 40, at anopening thereof that is greater than an outer diameter of theendoluminal prosthesis 12 in a relaxed expanded state. For someembodiments, an optional integral retraction tether 196 may be securedto and extend from the integral funnel section 190, as shown in FIGS. 37and 40-41, in order to further facilitate the eversion process andprovide an anchor point for the retraction end of the everting sheath172. As such, the integral retraction tether 196 may be secured to theretraction handle 186.

In some cases, an optional a nosecone 62 may be secured to the distalend 20 of the chassis 16, the nosecone 62 including a shoulder portion64 which is disposed within a distal end 198 of the tubular evertingsheath 172. The nosecone 62 may be secured to the chassis 16 in an axialposition which is distal of the endoluminal prosthesis 12 for someembodiments. In some instances, the chassis 16 may include a guidewirelumen 58 extending from the proximal end 18 of the chassis 16 to thedistal end 20 of the chassis 16. The chassis 16 may further include anaxial length of about 50 cm to about 200 cm for any of the embodimentsdiscussed herein. For the embodiments shown, a proximal adapter 19 issecured to the proximal end 18 of the chassis 16 and is configured toprovide an interface for a user of the catheter system 170 formanipulating the proximal end of the catheter system 170 or introducingmaterials or devices such as guidewires 60 or the like into variouslumens of the catheter system 170.

In some cases, the tubular endoluminal prosthesis 12 may be a tubularstent graft including at least one layer of thin, compliant material 70secured to a self-expanding stent 56. For some of these embodiments, thethin compliant material 70 may include nylon mesh, PTFE, ePTFE or thelike. In some instances, the stent graft 12 may be a fully stented stentgraft as shown in FIG. 9 wherein the helical resilient and undulatingstent 56 which is secured to the tubular graft material 70 extends allthe way from a distal end 26 of the stent graft to the proximal end 72of the stent graft 12.

In use, referring to FIGS. 42-45, a method for deploying the endoluminalprosthesis 12 in the body lumen 14 of a patient may include advancingthe catheter system 170 into the body lumen 14 of the patient until theendoluminal prosthesis 12 of the catheter system 170 is disposed at thetreatment site 74 in a constrained state as shown in FIG. 42. In somecases, advancing the catheter system 170 into the body lumen 14 of thepatient may include advancing the catheter system over a guidewire 60until the endoluminal prosthesis 12 of the catheter system is disposedat the treatment site 74 as discussed above in more detail with regardto other catheter system embodiments. The endoluminal prosthesis 12 maybe held in the radially constrained state by the inward radialconstraint imposed by a substantially non-expandable inside surface 200the endoluminal prosthesis section 178 of the inner section 174 of thetubular everting sheath 172. This outer constraint on the endoluminalprosthesis 12 may then be fully or partially removed from theendoluminal prosthesis 12 by proximally retracting and displacing theretraction end 182 of the outer section 180 of the tubular evertingsheath 172 relative to the chassis 16 and inner section 174 by aneversion process.

During the eversion process, the retraction end 182 and outer section180 of the everting sheath 172 are pulled back proximally relative tothe chassis 16 while the inner section 174 remains stationary but peelsup at the distal end as it folds back over on itself due to the axialdisplacement of the outer section 180 connected thereto. This processmay be continued until the outer section 180 and distal portion of theinner section 174 are everted proximally back from the endoluminalprosthesis section 178 of the inner section 174 as shown in FIG. 43.That is, eversion is carried out until the endoluminal prosthesissection 178 of the inner section 174 has been peeled back therebyexposing the endoluminal prosthesis and completely removing the inwardradial constraint of the endoluminal prosthesis section 178. Theendoluminal prosthesis 12 will thus be allowed to self-expand due tothis removal of the outer constraint. As the endoluminal prosthesis 12self-expands, an outside surface 76 of the endoluminal prosthesis 12 maythen engage an inside surface 78 of the patient's body lumen 14 as shownin FIG. 44. In most cases, the retraction end 182 of the outer section180 is proximally retracted until the everting sheath 172 and theconstraint imposed by the endoluminal prosthesis section 178 of theeverting sheath 172 is completely removed from the endoluminalprosthesis 12.

This method for deploying the endoluminal prosthesis 12 with cathetersystem 170 may be used to deploy any suitable variety of endoluminalprosthesis to any suitable target sites 74. FIG. 46 shows an endoluminalprosthesis 12 being deployed in an inner lumen 14 of an iliac artery ofa patient. The deployment of such an endoluminal prosthesis 12 at suchan iliac artery lumen may be carried out by any of the catheter systemembodiments and corresponding methods of use discussed herein.

In some cases, it may be useful to combine the endoluminal prosthesisretention capabilities of any of the catheter system embodiments 10,100, 126, 140 discussed above with the everting sheath deploymentcapabilities of the catheter system 170 or any other everting sheathcatheter system discussed herein. In this way, the axial position of theendoluminal prosthesis may be efficiently maintained during eversion ofthe everting sheath 172. Referring to FIG. 47, some embodiments of acatheter system embodiment 210 may include a flexible elongate chassis16 having a proximal end 18, a distal end 20, a distal section 22, alongitudinal axis 42, and an overall column strength sufficient foradvancement of the chassis 16 through a body lumen 14 of a patient. Thecatheter system 210 may also include a self-expanding tubularendoluminal prosthesis 12 disposed in a constrained state over thedistal section 22 of the chassis 16 and one or more thin, flexible,resilient extensions 24 that extend through a wall 34 of a distal end 26of the endoluminal prosthesis 12. The extensions 24 may be disposed in aradially constrained state such that each extension 24 at leastpartially captures a distal segment 36 of the endoluminal prosthesis 12and restricts proximal displacement of the endoluminal prosthesis 12relative to the chassis. The extensions 24 may each include a proximalend 28 which is secured in fixed relation to the elongate catheterchassis 16 and a distal end 30 which is disposed radially outward froman outside surface 32 of the chassis 16 and distal of the proximal end28 of the extension 24. The catheter system 210 includes a tubulareverting sheath 172 which has an inner section 174 which includes afixed end 176 which is secured in fixed relation to the chassis 16 andan endoluminal prosthesis section 178 that is disposed over and radiallyconstrains the endoluminal prosthesis 12 and extensions 24 in theconstrained state. The tubular everting outer sheath 172 may also havean outer section 180 that is everted back over the endoluminalprosthesis section 178 of the inner section 174. The outer section alsoincludes a retraction end 182 as shown in FIG. 31 which is disposed atan opposite end of the everting sheath 172 as the fixed end 176. Ingeneral, the catheter system 210 may include the same or similarfeatures, dimensions or materials as those of any of the cathetersystems discussed herein.

The everting sheath 172 is disposed over the endoluminal prosthesis 12and chassis 16 and includes an inner surface 200 of the endoluminalprosthesis section 178 that constrains the endoluminal prosthesis in theconstrained state. The inner surface 200 also radially constrains thedistal ends 30 of the extensions 24 in a radially constrained state asshown in FIG. 47. Such a radially constrained state of the distal ends30 of the extensions 24 may provide more leverage for the extensions 24to restrict proximal axial movement of the endoluminal prosthesis 12because the radial constraint on the distal ends 30 of the extensions 24prevents them from pivoting in a proximal direction when proximaltension is applied to the endoluminal prosthesis 12. For someembodiments, the extensions 24 may have distal ends 30 that extendradially outward from the chassis in a relaxed unconstrained state by adistance similar to a radius of the endoluminal prosthesis 12 to bedeployed when that endoluminal prosthesis 12 is also in an unconstrainedstate. In some instances, an angle the flexible extensions 24 form withrespect to the longitudinal axis 42 of chassis 16 may be 5 degrees to 50degrees with the extension 24 in a relaxed unconstrained state as shownin FIG. 8. The angle of the flexible extension 24 with respect to thelongitudinal axis 42 of the chassis 16 may in some cases be defined bythe angle between the longitudinal axis 42 of the chassis 16 and a lineextending from the proximal end 28 of the extension 24 to the distal end30 of the extension 24 as shown in FIG. 8.

Because of the resilience of some extension embodiments 24, the distalends 30 of these extensions 24 may be easily passed through the wall 34of the endoluminal prosthesis 12 when both the endoluminal prosthesis 12and the extension 24 are in a relaxed unconstrained state. Both theendoluminal prosthesis 12 and the extension 24 may be radiallyconstrained by an inward radial force and held in that constrained stateby the inner surface 200 of the of the inner section 174 of the evertingsheath 172 as shown in FIG. 47. In order to achieve both a properflexibility and resilience as well as sufficiently strong bending momentin order to resists failing under an axial load from the endoluminalprosthesis 12, some extension embodiments 24 may be made from aresilient high strength material such as a metal alloy or compositematerial. For some embodiments, the extensions 24 may be made from orinclude superelastic nickel titanium alloy. For some such embodiments,the extension 24 may include a transverse cross section area of about0.08 mm.sup.2 to about 1 mm.sup.2. For some embodiments, the extension24 may have a length of about 4 mm to about 25 mm. In some cases, thecatheter system 210 may include 1 extension 24 to 10 extensions 24, morespecifically 2 extensions 24 to 6 extensions 24 and even morespecifically 3 extensions 24 to 4 extensions 24.

In some cases, as shown in FIG. 7 and discussed above, the extensions 24may lie substantially in a same plane as the longitudinal axis 42 of thechassis 16. In some cases, substantially in the same plane includeswithin a thickness of the extension 24 of lying in the same plane as thelongitudinal axis 42 of the chassis 16. For some embodiments, theplurality of extensions 24 is evenly distributed with respect tocircumferential orientation about the chassis 16. In some cases, theextension 24 may have an s-shape in the unconstrained relaxed state asshown in more detail in FIG. 8. For the embodiment shown, the proximalmost deflection 46 of the s-shape of the extension extends away from thechassis 16 and a distal most deflection 50 of the s-shape of theextension 24 extends towards the chassis 16.

For some embodiments, the distal segment 36 of the endoluminalprosthesis 12 captured by the extension 24 includes a high strengthstent element 54 of a self-expanding stent 56 of the endoluminalprosthesis 12 as shown in FIG. 47. In some cases, the stent element 54captured by the extension 24 includes a crown section of the stent. Ahigh strength stent element 54 may include a resilient and optionallysuperelastic material such as nickel titanium alloy or the like.

For some embodiments, the chassis 16 may optionally include a guidewirelumen 58 extending from the proximal end 18 of the chassis 16 to thedistal end 20 of the chassis 16. In some instances, the catheter system210 may also include a nosecone 62 secured to a distal end 20 of thechassis 16 in an axial position which is distal of the endoluminalprosthesis 12. The nosecone 62 may also include a shoulder portion 64which is disposed within a distal end 198 of a tubular everting sheath172. For some embodiments, the tubular everting sheath 172 may bedisposed over the endoluminal prosthesis 12 and chassis 16 and includean inner surface 200 that at least partially radially constrains theendoluminal prosthesis 12 and one or more extensions 24 in theconstrained state. For some such embodiments, referring specifically toFIGS. 13-16, the shoulder portion 64 of the nosecone 62 may furtheroptionally include one or more elongate longitudinally oriented slots 68which are configured to accept the distal end 30 of the correspondingextensions 24 when the extensions 24 are in the radially constrainedstate. Some embodiments of these longitudinally oriented slots 68 may bedisposed so as to be substantially parallel to and lie substantially inthe same plane as the longitudinal axis 42 of the chassis 16. Thelongitudinally oriented slots 68 in the nosecone 62 may be useful insome instances for stabilizing the distal ends 30 of the one or moreextensions 24 when disposed in the radially constrained state.

In some cases, the tubular endoluminal prosthesis 12 may be a tubularstent graft including at least one layer of thin, compliant material 70secured to a self-expanding stent 56. For some of these embodiments, thethin compliant material 70 may include nylon mesh, PTFE, ePTFE or thelike. In some instances, the stent graft 12 may be a fully stented stentgraft, as shown in FIG. 9 and discussed above, wherein the helicalresilient and undulating stent 56 which is secured to the tubular graftmaterial 70 extends all the way from a distal end of the stent graft toa proximal end of the stent graft 12.

For catheter system embodiments 210 that include the stepped ormulti-diameter everting sheath 172, as shown in FIGS. 37-39, thediameter of the outer section 180 may be greater than the first diameterof the inner section 174 by an amount of at least a wall thickness 184of the outer section 180 of the tubular everting sheath 172 in somecases. For some embodiments, the diameter of the outer section 180 maybe greater than the diameter of the inner section 174 by an amount equalto 1 wall thickness of the everting sheath 172 to 4 wall thicknesses ofthe everting sheath 172. For some cases, the diameter of the innersection 174 and outer section 180 may be measured at a center of thewall thickness at diametrically opposed points of the wall of eachrespective section 174, 180.

The catheter system 210 includes the tubular everting sheath 172 withthe inner section 174 which includes a fixed end 176 which is secured infixed relation to the chassis 16 and the endoluminal prosthesis section178 that is disposed over and radially constrains the endoluminalprosthesis 12 and one or more extensions 24 in the constrained state.The tubular everting sheath 172 includes the outer section 180 that iseverted back over the endoluminal prosthesis section 178 of the innersection 174 as shown in FIG. 47. The outer section 180 of theseembodiments may include the retraction end 182 which may optionally besecured to the retraction handle 186 which is disposed at a proximalsection of the catheter system 210 and which is axially slidable withrespect to the chassis 16. The everting sheath 172 may include a PTFEmaterial having a closed cell microstructure with no distinct fibrilsinterconnecting adjacent nodes such that the outer section is readilyslideable over the inner section. Catheter system embodiments thatinclude an everting sheath including a PTFE material having a closedcell microstructure with no distinct fibrils may be configured with orwithout the dual diameter everting sheath 172 wherein the inner section174 has a different diameter than the outer section 180 as discussed inmore detail above.

In some cases, the everting sheath 172 or sections 174, 180 thereof mayinclude a layered tubular structure having a plurality of layers of thinpliable material which are secured together as shown in FIG. 39 anddiscussed above. An everting sheath 172 including a single layer ofmaterial or any layer of an everting sheath formed from a plurality oflayers may include any suitable pliable, low friction material such asnylon mesh, PTFE, ePTFE, the PTFE having a closed cell microstructurewith no distinct fibrils interconnecting adjacent nodes as discussedabove or any other suitable material.

In some cases, for everting sheath embodiments 172 that include PTFEmaterial and particularly ePTFE material, the everting sheath materialmay include an anisotropic orientation that provides a greater strengthin a first direction relative to a second direction perpendicular to thefirst direction. For example, a layer of ePTFE material that has ananisotropic orientation providing greater strength in a longitudinaldirection may be of particular use for an outer section 180 of theeverting sheath 172 which is subjected to longitudinal tensile forcesduring eversion of the everting sheath 172. For other embodiments, alayer of ePTFE material that has an anisotropic orientation providinggreater strength in a circumferential direction may be of particular usefor an inner section 174 of the everting sheath 172 which is subjectedto outward radial forces of the constrained self-expanding endoluminalprosthesis 12 disposed in the endoluminal prosthesis section 178 of theinner section 174.

For some embodiments of the catheter system 210, any of the evertingsheath embodiments 172 may further include one or more thin, elongate,high tensile retraction tethers 188 disposed between adjacent layers ofthe layered tubular structure of the everting sheath 172 and extendinglongitudinally along the endoluminal prosthesis section 178 and outersection 180 of the everting sheath 172 as shown in FIGS. 39 and 40. Forsingle layer everting sheath embodiments 172, such retraction tethers188 may be secured to either surface of the everting sheath 172. In somecases, the one or more retraction tethers 188 may be helically woundabout a tubular structure of the everting sheath 172 as shown in FIG. 40and discussed above.

In some cases, the everting sheath 172 of the catheter system 210 mayinclude an optional integral funnel section 190 disposed at theretraction end 182 of the outer section 180 of the everting sheath 172as shown in FIGS. 40 and 41. The funnel section 190 may be useful forboth loading an endoluminal prosthesis 12 into the everting sheath 172as well as facilitating relative movement between the outer section 180and inner section 174 during eversion. In some cases, the funnel section190 may have an inclusive funnel angle 192 of 10 degrees to 40 degrees.For some embodiments, the funnel section 190 may have a major diameterat an opening thereof that is greater than an outer diameter of theendoluminal prosthesis 12 to be deployed in a relaxed expanded state.For some embodiments, an optional integral retraction tether 196 may besecured to and extend from the integral funnel section 190, as shown inFIGS. 37 and 40-41, in order to further facilitate the eversion processand provide an anchor point for the retraction end 182 of the evertingsheath 172.

The chassis 16 may further include an axial length of 50 cm to 200 cmfor some embodiments. For the embodiments discussed herein, a proximaladapter 19 may be secured to the proximal end 18 of the chassis 16 andconfigured to provide an interface for a user of the catheter system 210for manipulating the catheter system 210 or introducing materials ordevices such as guidewires 60 or the like into various lumens of thecatheter system 210.

In use, referring to FIGS. 48-52, a method for deploying the endoluminalprosthesis 12 in a body lumen 14 of a patient may include advancing thecatheter system 210 for deployment of the endoluminal prosthesis 12 intothe body lumen 14 of the patient until the endoluminal prosthesis 12 ofthe catheter system 210 is disposed at a treatment site 74 as shown inFIG. 48. In some cases, the catheter system 210 may be advanced over theguidewire 60 as shown in FIG. 48. For such a catheter system 210, theendoluminal prosthesis 12 and the resilient, flexible, extension 24 thatat least partially captures the distal segment 36 of the endoluminalprosthesis 12 may both be held in a constrained state by the endoluminalprosthesis section 178 of the inner section 174 of the tubular evertingsheath 172. The outer constraint may thereafter be removed from theendoluminal prosthesis 12 and the extensions 24 by proximally retractingthe retraction end 182 of the outer section 180 of the tubular evertingsheath 172 as seen in FIG. 49. Retraction of the outer section 180 maybe carried out by the outer section 180 being everted back over theendoluminal prosthesis section 178 of the inner section 174 during theproximal retraction as indicated by the arrow 212 in FIG. 49. Thiseversion process may be carried out while the extensions 24 preventproximal axial movement of the endoluminal prosthesis 12 relative to aflexible, elongate chassis 16 of the catheter system 210. In some cases,the outer section 180 is proximally retracted until the everting sheath172 and constraint imposed by the endoluminal prosthesis section 178thereof is completely removed from the endoluminal prosthesis 12 andextensions 24 as shown in FIG. 50.

The endoluminal prosthesis 12 and distal ends 30 of the extensions 24may thereafter self-expand until an outside surface 76 of theendoluminal prosthesis 12 engages an inside surface 78 of the patient'sbody lumen 14 as shown in FIG. 50. Finally, the chassis 16 andextensions 24 may be proximally retracted as indicated by arrow 214 inFIG. 50, such that the extensions 24 pass axially through perforationsin the wall 34 of the distal end 26 of the endoluminal prosthesis 12 andno longer capture the respective distal segments 36 of the endoluminalprosthesis 12, as shown in FIG. 51. The chassis 16 and extensions 24 maybe further proximally retracted until they are no longer disposed withinthe lumen 216 of the endoluminal prosthesis 12 as shown in FIG. 52.

For the embodiment shown, the proximal end 28 of the extensions 24 aresecured in fixed relation to the elongate catheter chassis 16 and thedistal ends 30 of the extensions 24 are disposed radially outward froman outside surface 32 of the chassis 16 distal of the proximal ends 28of the extensions 24 such that allowing the endoluminal prosthesis 12and extensions 24 to self-expand includes allowing the distal ends 30 ofthe extensions 24 to pivot outwardly away from the chassis 16.

For some of the catheter system embodiments discussed above, loading aself-expanding endoluminal prosthesis 12, as well as any associatedcatheter system components such as a chassis 16 etc., into any of thecatheter systems discussed herein may be difficult, particularly sincelarge radial and frictional forces may be mutually imposed between thevarious components of the catheter system. In addition, many of thecomponents of such catheter systems may be fragile or easily damagedwhen subjected to improper types of forces and contact. As such, it maybe desirable to have a suitable method for loading endoluminalprostheses 12 into a catheter system and into a constrained state.Referring to FIGS. 53-58, a method of loading a self-expanding (or anyother suitable type) of endoluminal prosthesis 12 into a sheath, such asthe everting sheath embodiments 172 discussed above, is shown. Themethod embodiment shown includes passing a plurality of thin hightensile tether loops 220 through an end of the endoluminal prosthesis 12as shown in FIG. 53. The plurality of tether loops 220 may also bepassed through an inner lumen 222 of the everting sheath 172 also asshown in FIG. 53. In some cases, the tether loops 220 may be made fromany suitable high tensile flexible material including solid wires orbraided or stranded filaments of metals including metal alloys such asstainless steel, superelastic nickel titanium as well as high strengthpolymers such as nylon, aramid fibers and the like.

An end of the everting sheath 172 may be restrained such as by theintegral retraction tether 196 of the funnel section 190 as discussedabove and shown in FIG. 53 or by any other suitable method. Both ends ofeach of the tether loops 220 may be pulled on with axial tension beingsimultaneously applied to both ends of each tether loop 220 in adirection away from the endoluminal prosthesis 12. The axial tension isapplied to both ends of each tether loop 220 such that the tether loops220 are pulled through the inner lumen 222 of the everting sheath 172and axial tension is thereby applied to the end of the endoluminalprosthesis 12. The axial tension is applied to the endoluminalprosthesis 12 such that the endoluminal prosthesis 12 is thereby pulledinto the inner lumen 222 of the everting sheath 172 to an endoluminalprosthesis section 178, or any other desired section, within the innerlumen 222 of the sheath 172 as shown in FIG. 54. As shown in FIG. 53 theendoluminal prosthesis 12 is first pulled into the funnel section 190prior to entering the inner section 174. The funnel section 190 may beuseful for guiding and compressing the endoluminal prosthesis into theinner section 174. Thereafter, by pulling on only one side of each ofthe tether loops 220 and releasing an opposite end of each tether loop220, each of the tether loops 220 may slide through and be completelypulled out of the endoluminal prosthesis 12 and the inner lumen 222 ofthe sheath 178 as shown in FIGS. 56-58.

As shown in FIGS. 53-58, the loading method may also be used to loadboth an endoluminal prosthesis 12 and a corresponding chassis 16including flexible resilient extensions 24 extending therefrom. In suchinstances, the tether loops 220 may be used to pull the endovascularprosthesis, chassis and associated extensions 24 into the inner lumen222 of the everting sheath 172. As this combined structure is beingdrawn into the inner lumen 222 due to the axial tension applied to thetether loops 220, both the self-expanding endoluminal prosthesis anddistal ends 30 of the extensions 24 will be compressed and radiallyconstrained. The combined structure may be pulled through the innerlumen 222 until the endoluminal prosthesis 12 is disposed at theendoluminal prosthesis section 178 of the inner section 174 or disposedat any other desired location within the inner lumen 222.

As shown in FIGS. 53-58, the sheath being loaded is an everting sheath172 and pulling the tethers 220 may include pulling the tethers 220through the everting sheath 172 until the endoluminal prosthesis 12 isdisposed within and constrained by an endoluminal prosthesis section 178of the inner section 174 of such an everting sheath 172. However, suchmethods may also be used for any other suitable sheath embodiments,including any of the proximally retractable outer sheath embodimentsdiscussed herein that are configured to at least partially constrain aself-expanding endoluminal prosthesis 12, also as discussed above.

The delivery system and method embodiments discussed herein may beparticularly useful for endoluminal prosthesis embodiments which includeone or more inflatable portions. Such inflatable endoluminal prosthesisembodiments that may be deployed by the systems and methods discussedherein are discussed in U.S. Pat. No. 7,147,660 filed by M. Chobotov etal. on Dec. 20, 2002, titled “Advanced Endovascular Graft” which ishereby incorporated by reference herein in its entirety.

Delivery catheter embodiments discussed herein may include some or allof the features, dimensions or materials of delivery systems discussedin commonly owned U.S. Patent Application Publication No. 2004/0138734,published Jul. 15, 2004, filed Oct. 16, 2003, by Chobotov et al., titled“Delivery System and Method for Bifurcated Graft” and in PCTInternational Publication No. WO 02/083038, published Oct. 24, 2002,filed Apr. 11, 2001, by Chobotov et al., titled “Delivery System andMethod for Bifurcated Graft” each of which is incorporated by referenceherein in its entirety.

Endoluminal prosthesis embodiments discussed herein may include some orall of the features, dimensions or materials of the prostheses discussedin commonly owned U.S. Patent Publication No. 2009/0099649, filed Oct.3, 2008, by Chobotov et al., titled Modular Vascular Graft for LowProfile Percutaneous Delivery, which is incorporated by reference hereinin its entirety.

Examples of deployment devices, alignment devices, radiopaque markersdelivery methods and the like that may be used in conjunction with anysuitable system or component thereof discussed herein may be found incommonly owned U.S. Patent Application No. 2011/0218609, filed Feb. 9,2011, by M. Chobotov et al., and titled “Fill Tube Manifold and DeliveryMethods for Endovascular Graft”, and U.S. Patent Publication No.2013/0268048, filed Mar. 15, 2013, by J. Watson et al., and titled“Delivery Catheter for Endovascular Device”, U.S. Patent Publication No.2013/0268044, filed Mar. 13, 2013, by D. Parsons et al., and titled“Durable Stent Graft with Tapered Struts and Stable Delivery Methods andDevices”, each of which is hereby incorporated by reference herein inits entirety.

The entirety of each patent, patent application, publication anddocument referenced herein hereby is incorporated by reference. Citationof the above patents, patent applications, publications and documents isnot an admission that any of the foregoing is pertinent prior art, nordoes it constitute any admission as to the contents or date of thesepublications or documents.

Modifications may be made to the foregoing without departing from thebasic aspects of the embodiments discussed. Although embodiments havebeen described in substantial detail with reference to one or morespecific embodiments, those of ordinary skill in the art will recognizethat changes may be made to the embodiments specifically disclosed inthis application, yet these modifications and improvements are withinthe scope and spirit of the disclosure.

Embodiments illustratively described herein suitably may be practiced inthe absence of any element(s) not specifically disclosed herein. Thus,for example, in each instance herein any of the terms “comprising,”“consisting essentially of,” and “consisting of” may be replaced witheither of the other two terms. The terms and expressions which have beenemployed are used as terms of description and not of limitation and useof such terms and expressions do not exclude any equivalents of thefeatures shown and described or portions thereof, and variousmodifications are possible. The term “a” or “an” can refer to one of ora plurality of the elements it modifies (e.g., “a reagent” can mean oneor more reagents) unless it is contextually clear either one of theelements or more than one of the elements is described. Thus, it shouldbe understood that although embodiments have been specifically disclosedby representative embodiments and optional features, modification andvariation of the concepts herein disclosed may be resorted to by thoseskilled in the art, and such modifications and variations are consideredwithin the scope of this disclosure.

Certain embodiments of the technology are set forth in the claim(s) thatfollow(s).

What is claimed is:
 1. A catheter system for deploying an endoluminalprosthesis in a body lumen of a patient, comprising: a flexible elongatechassis having a proximal end, a distal end, a distal section and anoverall column strength sufficient for advancing of the chassis throughthe body lumen of the patient; the endoluminal prosthesis, theendoluminal prosthesis being a self-expanding tubular endoluminalprosthesis disposed in a constrained state over the distal section ofthe chassis; and a thin, flexible, resilient extension comprising: aproximal end secured in fixed relation to the chassis, a distal enddisposed radially outward from an outside surface of the chassis anddistal of the proximal end of the extension; wherein the extensionextends through a wall of a distal end of the endoluminal prosthesiswith the extension in a radially constrained state such that theextension at least partially captures a distal segment of theendoluminal prosthesis and restricts proximal displacement of theendoluminal prosthesis relative to the chassis, wherein the extensioncomprises an s-shape in an unconstrained relaxed state.
 2. The cathetersystem of claim 1, wherein a proximal most deflection of the s-shape ofthe extension and a distal most deflection of the s-shape of theextension extend in different directions.
 3. The catheter system ofclaim 2, wherein the catheter system further comprises a tubular outersheath disposed over the endoluminal prosthesis and chassis; and thetubular outer sheath comprises an inner surface that constrains theendoluminal prosthesis in the constrained state.
 4. The catheter systemof claim 4, wherein an outward facing curvature of the proximal mostdeflection corresponds to a rounded profile shaped for passage withinthe constraining tubular structure.
 5. The catheter system of claim 2,wherein the proximal most deflection provides a gap between an outersurface of the chassis and the extension.
 6. A catheter system fordeploying an endoluminal prosthesis in a body lumen of a patient,comprising: a flexible elongate chassis having a proximal end, a distalend, and a column strength configured for advancement of the chassisthrough a body lumen of a patient; a self-expanding tubular endoluminalprosthesis disposed in a constrained state at the distal end of thechassis; and a tubular everting sheath which comprises: an inner sectionwhich comprises a first diameter, a fixed end which is secured in fixedrelation to the chassis and an endoluminal prosthesis section that isdisposed over and radially constrains the endoluminal prosthesis in theconstrained state, and an outer section that is everted back over theendoluminal prosthesis section of the inner section, the outer sectioncomprising a retraction end and a second diameter which is larger thanthe first diameter of the inner section such that the outer section isreadily slideable over the inner section during retraction of theretraction end and eversion of the everting sheath.
 7. The cathetersystem of claim 6, wherein the second diameter of the outer section isgreater than the first diameter of the inner section by an amount of atleast a wall thickness of the outer section of the tubular evertingsheath.
 8. The catheter system of claim 6, further comprising: anintegral funnel section disposed at the retraction end of the outersection of the everting sheath, wherein the funnel section has a majordiameter at an opening thereof that is greater than an outer diameter ofthe endoluminal prosthesis in a relaxed expanded state; and a retractiontether secured to and extends from the integral funnel.
 9. The cathetersystem of claim 6, further comprising a nosecone, wherein at least oneof: the nosecone is secured to the chassis in an axial position which isdistal of the endoluminal prosthesis; or the nosecone is secured to thedistal end of the chassis, the nosecone comprising a shoulder portionwhich is disposed within a distal end of the tubular everting sheath.10. The catheter system of claim 6, further comprising a proximaladapter secured to a proximal end of the chassis.
 11. The cathetersystem of claim 6, wherein the chassis comprises a guidewire lumenextending from the proximal end of the chassis to the distal end of thechassis.
 12. The catheter system of claim 6, wherein the tubularendoluminal prosthesis comprises a tubular stent graft comprising atleast one layer of compliant material secured to a self-expanding stent;and the stent graft comprises a fully stented stent graft.
 13. Acatheter system for deploying an endoluminal prosthesis in a body lumenof a patient, comprising: a flexible elongate chassis having a proximalend, a distal end, and a column strength configured for advancement ofthe chassis through a body lumen of a patient; a self-expanding tubularendoluminal prosthesis disposed in a constrained state at the distal endof the chassis; and a tubular everting sheath which comprises an innersection which comprises a fixed end which is secured in fixed relationto the chassis and an endoluminal prosthesis section that is disposedover and radially constrains the endoluminal prosthesis in theconstrained state, an outer section that is everted back over theendoluminal prosthesis section of the inner section, the outer sectioncomprising a retraction end, and a PTFE material having a closed cellmicrostructure with no distinct fibrils interconnecting adjacent nodessuch that the outer section is readily slideable over the inner section.14. The catheter system of claim 13, wherein the everting sheathcomprises a layered tubular structure comprising a plurality of layersof compliant PTFE material which are secured together; the PTFE materialstructure layup is anisotropically oriented for strength along at leastone of a longitudinal direction of the everting sheath or acircumferential direction of the everting sheath.
 15. The cathetersystem of claim 14, further comprising a thin, elongate, high tensileretraction tether disposed between adjacent layers of the layeredtubular structure of the everting sheath and extending longitudinallyalong the endoluminal prosthesis section and outer section of theeverting sheath.
 16. The catheter system of claim 15, further comprisinga plurality of thin, elongate, high tensile retraction tethers disposedbetween two adjacent layers of the layered tubular structure of theeverting sheath, wherein the plurality of thin, elongate, high tensileretraction tethers are helically wound about a tubular structure of theeverting sheath.
 17. A method of loading an endoluminal prosthesis intoa sheath which is configured to constrain the endoluminal prosthesis,comprising: passing a plurality of thin high tensile tethers loopsthrough an end of the endoluminal prosthesis; passing the plurality oftether loops through an inner lumen of the sheath; restraining an end ofthe sheath and pulling on both ends of each of the tether loopssimultaneously such that the tether loops are pulled through the innerlumen of the sheath so as to apply tension to the endoluminal prosthesissuch that the endoluminal prosthesis is radially compressed andconstrained as it is pulled into the inner lumen of the sheath to anendoluminal prosthesis section within the inner lumen of the sheath; andthereafter pulling on only one side of each of the tether loops andreleasing an opposite end of each tether loop until each of the tetherloops is pulled out of the endoluminal prosthesis and the inner lumen ofthe sheath.
 18. The method of claim 17, wherein the sheath configured toconstrain the endoluminal prosthesis comprises an everting sheath of acatheter system.
 19. The method of claim 18, wherein the sheathcomprises an everting sheath and wherein pulling the tethers comprisespulling them through the everting sheath until the endoluminalprosthesis is disposed within and constrained by an endoluminalprosthesis section of an inner section of the everting sheath.
 20. Themethod of claim 17, wherein the sheath configured to constrain theendoluminal prosthesis comprises a proximally retractable outer sheathof a catheter system.